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Jamison DT, Feachem RG, Makgoba MW, et al., editors. Disease and Mortality in Sub-Saharan Africa. 2nd edition. Washington (DC): The International Bank for Reconstruction and Development / The World Bank; 2006.

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Disease and Mortality in Sub-Saharan Africa. 2nd edition.

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Chapter 21Cardiovascular Disease

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The burden of cardiovascular disease (CVD) in the world is enormous and growing, and the majority of those affected are in developing countries (Beaglehole and Yach 2003; Mbewu 1998). In 2002 it was estimated that 29 percent of deaths worldwide (16.7 million deaths) were due to CVD and that 43 percent of global morbidity and mortality, measured in disability-adjusted life years (DALYs), was caused by CVD (WHO 2002). Furthermore, 78 percent of global mortality and 86 percent of mortality and morbidity from CVD occurs in developing countries. By 2020 it is estimated that CVD will become the leading cause of the global health burden, accounting for 73 percent of total global mortality and 56 percent of total morbidity (Murray and Lopez 1996; Reddy and Yusuf 1998).

Africa has not been spared this global tide of CVD. In most African countries CVD is now the second most common cause of death after infectious disease, accounting for 11 percent of total deaths (WHO 1999); and CVD is a major cause of chronic illness and disability. Projections from the Global Burden of Disease Project suggest that from 1990 to 2020, the burden of CVD faced by African countries will double. A large proportion of the victims of CVD will be middle-aged people. The poor will suffer disproportionately as a consequence of their higher disease risk and limited access to health care. The financial and social costs of this CVD epidemic are likely to have a negative impact on development and the alleviation of poverty (http://www.ichealth.org).

African countries therefore face a double burden as they struggle to cope with the burden of communicable diseases and diseases associated with lack of socioeconomic development—the "unfinished agenda." Furthermore, their predicament is only likely to worsen, because the majority of their populations are under 35 years of age, and the determinants and risk factors for CVD are already prevalent and increasing within this age group.

The relative cost of the epidemic of CVD is likely to be higher than in upper-income countries, where CVD primarily affects the elderly. In African countries more than half of CVD deaths occur among people between 30 and 69 years of age, an age 10 years or more below the equivalent group in Europe and North America (http://www.ichealth.org). In Ghana, for example, where cerebral hemorrhage is a leading cause of death, the average age at which people die from this cause is 55 years (http://www.ichealth.org). Death and disability in middle age have major social and economic consequences, depriving families of parents, workplaces of employees, and communities of leaders. Patients denied access to health care for CVD or deterred by high costs from seeking it will cause the public health systems to incur even greater health care costs in the long run as a result of the need to treat the same patients later at greater expense because the disease is more advanced.

The potential costs of this CVD epidemic for African countries are staggering. Cardiovascular disease (direct and indirect) is estimated to cost the United States about US$300 billion annually, equal to the entire gross domestic product of the African continent. Clearly, even a fraction of such cost has the potential to cause enormous damage to the economies and development trajectories of African countries. In this way, the growing CVD epidemic in Africa will increase already unacceptable levels of inequity in access to health care services.

The overall health of African nations will not improve, nor will their level of development, unless they deal with this epidemic of CVD. Furthermore, in an increasingly integrated global economy the CVD epidemic in developing countries will divert economic goods to CVD care, resulting in a reversal of developmental efforts; productivity will decline because of the loss of more productive citizens; and consumer markets will shrink as a result of loss of the purchasing power of these citizens.

The Epidemiological Transition

The process responsible for these global shifts in CVD mortality is termed the "epidemiological transition" (Omran 1971). Three main drivers fuel this transition:

  • Declining infant and child mortality has led to rapid demographic changes resulting in large increases in the number of individuals surviving until middle and older age, when chronic diseases become manifest—the so-called demographic transition. By 2025 it is estimated that the number of Africans over 60 years old will increase from 39 million to 80 million.
  • Falling death rates from communicable diseases have accompanied socioeconomic development and improved vaccination and other primary health care services.
  • Changes have occurred in environmental and behavioral determinants of CVD, such as increasing tobacco use, increasing fat and calorie consumption, and decreasing exercise. Longer periods of exposure to these determinants because of longer life expectancy have increased the rates of chronic disease.

Moreover, whereas European and North American populations experienced similar changes in demography, determinants, and disease rates over the course of a few centuries, African countries are passing through similar transitions in just a few decades (http://www.ichealth.org). This forced pace of globalization has resulted in the "export of risk factors" from the West such as tobacco, refined foods, and lifestyles with high CVD risk that are portrayed on television and film (Mbewu 1998).

Still, the process of epidemiological transition seems to be different in Africa than in developed and other developing countries, where it is mainly marked by the explosion of coronary heart disease (CHD). Indeed, although the epidemic of CHD was heralded in the 1980s (Ogunnowo, Odesanmi, and Andy 1986), in Africa it is still awaited, although hemorrhagic stroke is already a leading cause of mortality and morbidity (Walker et al. 2003). Furthermore, dilated cardiomyopathy is particularly prevalent in Sub-Saharan Africa, presumably owing to nutritional and viral factors. The epidemiological transition was readily apparent in the changes in causes of mortality in the Seychelles over the past 30 years (table 21.1) (Bovet 1995).

Table 21.1. The Epidemiological Transition in the Seychelles, 1976 and 1994(percent).

Table 21.1

The Epidemiological Transition in the Seychelles, 1976 and 1994(percent).

More reasons to suspect an impending epidemic of CVD in Sub-Saharan Africa include the recent finding that poor socioeconomic conditions in childhood determine CVD in middle age as strongly as do CVD risk factors in middle age in the same individuals (Lawlor, Smith, and Ebrahim 2002). Furthermore, according to the Barker Hypothesis, poor fetal growth has been shown to be associated with hypertension, and CVD, in later life. However, a study carried out in Nigeria failed to demonstrate this effect (Law et al. 2001). The current impoverishment of much of Sub-Saharan Africa may paradoxically result in an epidemic of CVD in middle age for those who survive the ravages of poverty-associated communicable diseases, such as AIDS, tuberculosis, pneumonia, and malaria. Because fetal growth retardation is associated with chronic undernutrition among women, improvement in the nutrition and health of girls and young women may be important in preventing CVD in developing countries.

Sources of Data

Sources of data on CVD rates in Sub-Saharan Africa are generally lacking, and when present, are often of poor quality. Much of the available data comes from individual studies, often hospital-based, with small numbers of participants. Often the different data sources are heterogenous in methodology and cannot be compared; and systematic and regular surveillance systems are almost totally absent, making it difficult to plot changes in CVD rates over time. Nevertheless, the available data sources do give some idea of the nature and magnitude of CVD in Sub-Saharan Africa and of the changes in the nature and rates of CVD that have taken place over the past 50 years.

Measures of Cardiovascular Mortality

Globally, cause-of-death data based on the death certificate as provided to the data bank of the World Health Organization (WHO) is available in only 77 countries. There is wide regional variation in coverage by national vital registration systems, ranging from 80 percent population coverage in the European region to less than 5 percent in the Eastern Mediterranean and African regions of WHO (Sen and Bonita 2000). The most serious gap is for adult mortality, crucial if one is to gauge the true extent of CVD in the developing world and monitor trends over time.

The 10-fold variation in infant mortality between different regions of the world is largely due to communicable disease, malnutrition, and poverty, whereas the cause of death in adults age 15 to 60 is almost entirely due to noncommunicable diseases (NCDs) and injury (Murray and Lopez 1997). Men in Sub-Saharan Africa are three times more likely to die prematurely than men in Western industrial populations as a result of AIDS and violence.

Verbal autopsy has been shown to be an economical and useful way of improving the quality of cause-of-death information when health workers have minimal training. For example, in an investigation of causes of death in women of childbearing age in Guinea-Bissau, 70 percent of deaths could be attributed to a specific disease or condition (Sen and Bonita 2000).

Cardiovascular Surveillance Systems

Data on the incidence and prevalence of CVD is scanty. Surveillance should become a critical component in the strategies adopted in Sub-Saharan Africa to deal with the burgeoning epidemic of CVD. Sentinel surveillance is likely to be the preferred methodology, whereby monitoring of disease episodes is periodically conducted at sentinel sites that are broadly representative of the general population. This methodology is preferred because Sub-Saharan countries have limited resources, and their health systems cannot monitor every single disease episode. The systems set in place should include behavioral surveillance, often dubbed "second generation surveillance." Demographic health surveys are cheaper to administer but suffer from the pitfall of their cross-sectional design. Surveillance will not only monitor the prevalence of CVD but will also help gauge the impact of primary prevention strategies.

Crude Mortality versus Age-Standardized Mortality

The importance of CVD mortality in Sub-Saharan Africa countries tends to be underestimated, because crude mortality rates rather than age-standardized mortality rates are used. Thus the appalling figures for infant mortality from infectious disease and diseases of poverty tend to overshadow all other causes of death. Yet, from the perspective of citizens of Sub-Saharan countries when contemplating their own mortality, or the policy maker when considering causes of death among economically active people, age-specific mortality ratios are critical. They are also important for the planner predicting the patterns of death in years to come. Age-standardized mortality ratios make it clear that the long-heralded epidemic of CVD in Africa has, at least in some African countries, already arrived. Indeed, in some middle-income countries, such as South Africa, age-standardized mortality rates are higher than for Scotland and Finland, and they are exceeded only by rates in the former socialist economies of Europe (figure 21.1) (Bradshaw et al. 2003).

Figure 21.1

Figure 21.1

Cardiovascular Disease, Age-Standardized Rates in the World, 1994–2000 (per 100,000 people) Source: Debbie Bradshaw (personal communication) and WHO Mortality Database, WHO Statistical Information System at http://www3.who.int/whosis/ (accessed (more...)

The Changing Prevalence, Incidence, and Pattern of Cardiovascular Disease

The relative and absolute importance of CVD in countries of Sub-Saharan Africa is thought to be increasing, but information on morbidity, mortality, and prevalence of disease and risk factors is scanty (Muna 1993b; Razum 1996). Data from 20 years ago consisted largely of hospital records, which reported that 8 to 12 percent of hospital admissions were due to heart disease in several countries in southern Africa (Vaughan 1977); hypertensive and rheumatic heart disease (RHD) accounted for 40 to 60 percent of these admissions. There were few recorded episodes of ischemic cardiac events. By 1977 such causes of death as syphilitic heart disease were rarely recorded, despite the continuing high frequency of acute syphilis. In the 1970s cardiac disease was common among young people in Kampala, Uganda, where autopsy data demonstrated cardiac disease to be a cause of death in 15.3 percent of males older than 60 years and in 13.1 percent of males younger than 30 years (Drury 1972). In 1980 the Zambian Ministry of Health report of admissions and causes of death in all government, mining, and mission hospitals listed 2.06 percent of deaths in those under age 14 years as cardiac in origin compared with 14.50 percent in those over age 14. As regards morbidity, 0.62 percent of hospital admissions of children under 14 in that same study were cardiac in origin compared with 4.23 percent of those individuals over age 14 (Hutt 1990).

By 1990, CVD had become the third most common cause of death in a prospective autopsy study in 90 of the 167 deaths in one year at Tshepong Hospital in the North West Province of South Africa (Steenkamp, Simson, and Theron 1992). In patients over age 35, CVD was the most common cause of death.

Cerebrovascular disease accounted for 32 percent of the CVD deaths overall. Among these, intracerebral hemorrhage was found in 50 percent and cerebral infarction in 29 percent of cases. Fifty-seven percent of cardiovascular deaths were due to cardiac conditions, the most common being pulmonary hypertension (31 percent), dilated cardiomyopathy and chronic rheumatic valvular disease (17 percent each), and hypertensive heart disease (14 percent). Only 3 percent of the examined vessels had signs of severe atherosclerosis. The clinical diagnosis was the same as the final autopsy diagnosis in only 38 percent of cases, emphasizing the importance of performing autopsies to obtain reliable mortality statistics in African countries.

In a prospective study among elderly patients in Kenyatta National Hospital, Nairobi, Kenya, in 1991 to 1992, clinical evidence of CVD was present in 40 percent of the patients evaluated; 54 percent were hypertensive, 53 percent had arrhythmia, and 49 percent had congestive cardiac failure (Lodenyo, McLigeyo, and Ogola 1997). A prospective study of 708 subjects with CVD was conducted between January 1992 and December 1995 in Ghana (Amoah 2000). Participants were evaluated clinically, with ancillary laboratory tests, chest X-ray, electrocardiography, and two-dimensional echocardiography with doppler and color flow mapping. Hypertensive heart disease (n = 133), RHD (n = 123), idiopathic cardiomyopathy (n = 103), congenital heart disease (n = 90), and coronary artery disease (CAD; n = 80) were the major causes of cardiovascular morbidity. The mean age of the subjects was 41.6; peak incidence of CVD occurred during the decile 40–49 years of age.

A retrospective study in 1995 in Cameroon of 312 adult patients with CVD, average age 44 years, revealed high blood pressure (38.5 percent), rheumatic valvular heart diseases (25.6 percent), cardiomyopathies (22.5 percent), and other cardiovascular diseases (13.5 percent) (Kotto and Bouelet 2000). Rheumatic valvulopathies were predominant among the age group 20 to 39 years, hypertension was predominant from the age of 40 years, and cardiomyopathies were observed in the age range 20 to 60 years.

A Cameroonian study between 1992 and 1997 ranked coronary artery disease eighth among the CVDs registered with a prevalence of 1.53 percent (2.42 percent in males and 0.45 percent in females). Myocardial infarction was the most frequent clinical form of CAD observed (43 percent), followed by angina pectoris (23 percent), unstable angina (20 percent), and other forms of ischemic heart disease (13 percent). The cardiovascular risk factors were obesity (80 percent), hypertension (60 percent), dyslipidemia (43 percent), smoking (36 percent), diabetes/hyperglycemia (26 percent), and hyperuricemia (20 percent). Seventy-six percent of the patients had at least three cardiovascular risk factors (Mbanya et al. 1998).

In multiethnic South Africa, CHD is the major cause of death among white people and South Africans of Indian descent, with incidence rates of 165.3 and 101.2 per 100,000 people, respectively, but only 55.1 per 100,000 among people of mixed descent and 5.3 per 100,000 among black African people. Cerebrovascular disease is the most common cause of CVD death among those of mixed descent, followed by white people and South Africans of Indian descent, and then black African people (73.6, 62.5, and 36.5 per 100,000, respectively) (Bradshaw et al. 2003).

In South Africa 90 percent of deaths are certified; of these certifications over 70 percent are by a medical doctor, and cause-specific data are available for most deaths. A gradually shrinking proportion, currently 13 percent, are categorized as "ill-defined." It is quite possible that many deaths from CVD could masquerade as ill-defined deaths, particularly in a country where there is still a reluctance to diagnose CVD death in black people.

Epidemiology of the Various CVDs

With such inadequate data sources, it is inevitable that the epidemiology of CVD in Sub-Saharan Africa will be poorly understood.

Cerebrovascular Accidents

The prevalence and incidence of stroke in Sub-Saharan Africa have increased over the last half century, due principally to increased life expectancy and changes in environmental determinants and risk factors. The majority of cerebrovascular accidents (CVAs) occur in young and middle-aged people and are related to hypertension. Hypertension is highly prevalent in Sub-Saharan Africa and is often undetected or poorly controlled. This may be the explanation for the high proportion of hemorrhagic CVAs, whereas in developed countries most CVAs occur in older people and are thrombotic in etiology. This has been confirmed by clinical, radiological, and postmortem diagnostic methods. Overall, CVAs account for 7 percent of deaths in South Africa (Statistics South Africa 1996).

Cross-sectional, hospital-based studies of the prevalence and incidence of CHD and stroke and associated risk factors have been carried out in South Africa, central Africa, West Africa, and North Africa (Ezenwaka et al. 1997; Vorster 2002; Walker and Sareli 1997; Wiredu and Nyame 2001). In the city of Tunis in Tunisia the crude annual incidence rate of stroke has been estimated at 54 per 100,000 and the prevalence rate at 600 to 1,400 per 100,000. The incidence rate adjusted to population at risk (greater than or equal to 45 years old), is about 192 per 100,000. A door-to-door survey conducted in the town of Kelibia in Tunisia showed a prevalence rate of 720 per 100,000 when adjusted to population at risk. The crude incidence rate of stroke was estimated to be between 1 and 30 per 100,000; and the standardized rate was 68 per 100,000. Fifty percent of the stroke victims were below the age of 54 years; and one-third of them died within one week of the stroke. Overall, the age-specific rates for both sexes rose with age, with the rates for women being higher at all age strata except for the group age 45 to 54 years (Mirabet 1990). In a South African study of stroke patients in 1998, only 20 percent of the total group understood that hypertension had probably caused their stroke, although 76 percent of the older group and 56 percent of the younger group had been told at some stage that they were hypertensive (Hale, Fritz, and Eales 1998).

In a study of CVA in 21 centers in Africa, Asia, Europe, and Latin America, using computed tomography (CT) scan, magnetic resonance imaging (MRI), or cerebral angiography, the overall odds ratio of ischemic stroke was 2.99 (95 percent CI, 1.65–5.40) in Europe and 2.93 (2.15–4.00) in the non-European (developing) countries.

Table 21.2 shows data on incidence of stroke in Sub-Saharan Africa from a review of literature on hospital studies in Africa (Rosman 1986), a population-based study in Nigeria (Osuntokun et al. 1987), and a hospital study in Zimbabwe (Matenga 1997).

Table 21.2. Incidence of Stroke.

Table 21.2

Incidence of Stroke.

In Mauritius between 1990 and 1994 (Sarti et al. 2000) the age-standardized stroke mortality for women and men age 35 to 74 years was 268 per 100,000 and 138 per 100,000, respectively.

In Tanzania, recent verbal autopsy data demonstrated that the age-adjusted stroke mortality rates were high (Walker et al. 2000). During the three-year observation period 11,975 deaths were recorded in three surveillance areas, of which 7,629 (64 percent) were of adults age 15 years or older; of these, 4,088 (54 percent) were of men and 3,541 (46 percent) were of women. CVD accounted for 421 (5.5 percent) of the deaths; of these, 225 (53 percent) were of men and 196 (47 percent) were of women. The yearly age-adjusted rates per 100,000 in the 15-to-64-year age group for the three project areas (urban, fairly prosperous rural, and poor rural) were 65 (95 percent CI, 39–90), 44 (31–56), and 35 (22–48), respectively, for men, and 88 (48–128), 33 (22–43), and 27 (16–38) for women. In a hospital-based study of 116 patients in Pretoria, one-month mortality was 33.6 percent (Rosman 1986).

Coronary Heart Disease

CHD, clinically manifested as ischemic heart disease (IHD), was formerly rare in Sub-Saharan Africa, again probably largely because the majority of Africans did not live long enough to suffer the clinical manifestations of angina, acute ischemic syndromes, myocardial infarction, and heart failure that usually develop in middle and old age. Still, even in those Africans who did live long enough for the cumulative effects of risk factors for CHD to take effect, CHD was rare up until the mid-twentieth century as evidenced by 3,500 postmortem studies in Ghana (Edington 1954) in which only three cases of CHD were found; of 635 cases of cardiac death in Uganda in 1966, 10 years later, less than 1 percent of CHD was found at autopsy (Hutt and Coles 1969). CHD has been increasing since the 1980s (Hutt 1990), however, with reports of clinical IHD and increasing CHD prevalence (Bertrand 1992; Hutt 1990). The risk factors seem to be the same as in Europe, but the risk index is 2.1 to 2.7 compared with 3.6 in France. Myocardial infarction at 49 percent was the most common manifestation of CHD, followed by angina pectoris at 32 percent; ischemic cardiomyopathy, 7 percent; and ventricular aneurysm, 7 percent (Bertrand 1992). Myocardial infarction in black Africans under age 40 years shows characteristics similar to those seen in patients under age 40 in the West, particularly regarding the frequency of myocardial infarction as the first manifestation of the disease, low prevalence of coronary artery stenosis, and a relatively common finding of normal coronary arteriography (Nethononda et al. 2004).

The increase in CHD in Sub-Saharan Africa since the 1980s is presumably because of the increasing prevalence among African populations of the classical risk factors for CAD: smoking, a diet high in saturated fat, hypertension, obesity, diabetes mellitus, and lack of physical exercise. In addition, life expectancy in Sub-Saharan Africa has risen since the 1950s, meaning that more people are exposed to these risk factors for long enough periods to cause CAD. A study of black African patients admitted to a coronary care unit with acute myocardial infarction between 1995 and 1996 showed high rates of smoking and hypertension among the patients compared with controls matched by age and sex (Mayosi et al. 1997).

A coronary angiographic study of black African patients with acute myocardial infarction and acute ischemic syndromes admitted to Chris Hani Baragwanath Hospital in Johannesburg, South Africa, showed a clear increase in prevalence of risk factors for CHD in these patients compared with age- and sex-matched controls (Nethononda et al. 2004). In coronary angiographic studies of black Africans following myocardial infarction, mild to moderate coronary artery disease is often found rather than the moderate to severe artery disease found in their white and Indian counterparts. Indeed, CHD is the most common cause of morbidity and mortality in South Africans of Indian descent (Seedat 1998).

The risk factor profile, then, for CHD is the same in Sub-Saharan Africa countries as in Western countries, but the hemoglobin S or C trait could be a risk factor for CHD unique to Sub-Saharan Africa. The long-term outcome of infarction is severe and influenced by myocardial sequelae of imprecise origin, delayed hospitalization, absence of thrombolysis and angioplasty, and socioeconomic and literacy problems.

Mortality from CHD is much more difficult to estimate than that from stroke without a population-based study in Sub-Saharan Africa. Steinberg, Balfe, and Kustner (1988) reported a 25 percent decline in age-adjusted mortality from IHD in South Africa, from 162 per 100,000 people in 1978 to 121 per 100,000 in 1985. Bertrand (1992) reported an inhospital mortality after myocardial infarction of 15 percent.

A recent case-control study of 98 black South Africans with CHD over 15 years culminated in 58 deaths from myocardial infarction with postmortem data available. Logistic regression analysis revealed that the classical risk factors in this cohort of patients operated in the same way as in Western populations (K. Steyn, unpublished observations). Similar results have been found in the soon-to-be published Interheart Study of risk factors for CHD among 15,152 patients around the world compared with age- and sex-matched controls. This included several hundred patients in South Africa from all ethnic groups and demonstrated that nine easily measured risk factors are associated with more than 90 percent of the risk. These results are consistent across all geographic regions and ethnic groups of the world, men and women, and young and old (Yusuf et al. 2004).

Rheumatic Heart Disease

Twenty years ago rheumatic heart disease (RHD) was the most common form of cardiac disease in Sub-Saharan Africa and still remains prevalent, with many young people in their teens and early twenties presenting with severe RHD (Ekra and Bertrand 1992). In the 1980s RHD accounted for 10 to 35 percent of hospital cardiac patients in Sub-Saharan Africa (Hutt 1990) and up to 20 percent of cardiac deaths noted at autopsy. Most of the cases occurred in young people. In Soweto, Johannesburg, South Africa, the incidence of RHD among primary schoolchildren was 6.9 per 1,000; and in Ibadan, Nigeria, the incidence was 3 per 1,000 among children (Hutt 1990).

A Ghanaian study reported the most common rheumatic valvular lesion to be mitral regurgitation (Amoah 2000). In a survey of 1,115 children in Kenya, 3 had clinical and echocardiographic evidence of RHD, giving a prevalence rate of 2.7 per 1,000 (Anabwani and Bonhoeffer 1996), whereas 6.2 percent had trivial mitral regurgitation; 0.3 percent, trivial aortic regurgitation; and 0.4 percent, isolated mild to moderate regurgitation of the pulmonary valve. Congenital heart disease was found in two children, one with secundum atrial septal defect and the other with a ventricular septal defect and pulmonary stenosis, giving a prevalence of 1.8 per 1,000.

RHD is a disease of poverty, related to overcrowding, poor housing, and undernutrition and requires a multisectoral response for prevention and cure. It is caused by group A beta-hemolytic streptococci. The principal methods of control are primary and secondary prevention of streptococcal infection. Specifically, these preventive measures entail prompt treatment of streptococcal throat infections with penicillin in primary prevention and penicillin prophylaxis following rheumatic fever in order to prevent rheumatic heart disease in secondary prevention. The lack of these preventive measures explains the persistence of rheumatic fever and RHD in Sub-Saharan Africa, which, compared with the rest of the world, has remained poor. Countries in Sub-Saharan Africa also lack adequate health systems for managing rheumatic fever and RHD.

Heart Failure

Systemic hypertension is the most common cause of heart failure among black Africans. In a study of 52 Gambians and 55 Nigerians between ages 16 and 69 years with hypertensive heart failure, the mean duration of diagnosis of systemic hypertension among the previously known hypertensives was 4.3 years (Isezuo et al. 2000). The overall one-year survival rate was 71 percent, although it was unclear whether this was largely systolic or diastolic heart failure and whether the cases were primarily essential hypertension or included large numbers with secondary hypertension. The prognosis of hypertensive heart failure among this population is poor, with the first three months from onset of heart failure being critical for survival. Early detection and control of systemic hypertension should be more aggressively pursued.

A 1993 study of patients admitted to Kenyatta National Hospital with congestive heart failure revealed that almost 32 percent had RHD, 25 percent had cardiomyopathy, 18 percent had hypertensive heart disease, 13 percent had pericardial disease, and 2 percent had ischemic heart disease (Oyoo and Ogola 1999).

RHD remains a major cause of heart failure in Africa, especially in the young, and hypertensive heart failure is common, unlike in developed countries, where improved blood pressure control has reduced the prevalence of this condition (Mendez and Cowie 2001). However, as African countries go through the epidemiological transition and develop socioeconomically, the epidemiology of heart failure becomes increasingly similar to that of Western Europe and North America, with CHD being the most common cause of heart failure. Preventive and public health strategies need to take cognizance of the local epidemiological characteristics.

Risk factors for cardiac failure in Brazzaville, Republic of Congo, from 1975 to 1999 were found to be arterial hypertension (53 percent), hypercholesterolemia (38 percent), smoking (28 percent), obesity (24 percent), and diabetes (5 percent) (Kimbally-Kaky and Bouramoue 2000). Risk factors for ischemic cardiopathy at the Hôpital Principal in Dakar, Senegal, were hypercholesterolemia (56 percent), tobacco smoking (44 percent), arterial hypertension (41 percent), diabetes (40 percent), and overweight (27 percent) (Thiam et al. 2000). Seventy-five percent of patients presented with coronary pain, and 50 percent had symptoms of cardiac insufficiency.

Dilated Cardiomyopathy

Dilated cardiomyopathy (DCM) resulting in congestive cardiac failure is surprisingly common in Sub-Saharan Africa, accounting for up to 20 percent of cardiac cases in some regions. Occasionally the disease is familial with specific candidate genes recently identified (Sliwa, Damasceno, and Mayosi 2005). A similar picture can be seen in beriberi and alcoholic cardiac disease. There may be a whole spectrum of causes of DCM, including genetic etiology, toxins, and vitamin or micronutrient deficiency, such as selenium deficiency. Dilated cardiomyopathy is often seen as a late complication of human immunodeficiency virus (HIV) infection (Fauci and Lane 2001).

In a Ghanaian study of 708 patients in a cardiac referral center, DCM was the most common form of cardiomyopathy, followed by hypertrophic cardiomyopathy and endomyocardial fibrosis (Amoah 2000). Treatment involves nonspecific management of the congestive cardiac failure, although cardioselective beta-blockade has been increasingly used. End-stage disease often necessitates cardiac transplantation, although this is rarely feasible in most African countries because of resource constraints.

Endomyocardial Fibrosis

Endomyocardial fibrosis (EMF) was first described in detail by J. N. P. Davies in Uganda in 1948 (Davies 1948). Fibrosis of the inflow tracts of the right and left ventricles results in mitral or tricuspid incompetence and impaired ventricular function, as a result of the restrictive deficit in which the stiff fibrotic ventricles cannot contract and relax normally. Patients usually present in their twenties or thirties. The disease is found in a broad swath across Africa, between the Sahara Desert in the north and the Zambezi River in the south. In temperate climates the disease is rare, presenting as Loeffler's endocarditis, a syndrome exhibiting marked eosinophilia. Consequently it has been suggested that EMF may be caused by an eosinophilic response to filariasis or malaria. Another hypothesis from Uganda implicates cassava protein in the etiology of EMF, but the geographical spread of the disease compared with areas where cassava is eaten does not support this as a sole etiological agent (Hutt 1990).

In a Kenyan study, patients with echocardiographically proven EMF recruited between 1993 and 1996 were found to have eosinophilia of more than 500 cells per microliter, compared with non-EMF cardiac patients, and general medical outpatients (Mayanja-Kizza et al. 2000). High eosinophilia of more than 1,000 cells per microliter was found in 38 percent of the EMF patients but only 6 percent of the non-EMF cardiac patients and in 5 percent of general medical patients. High levels of eosinophilia in the range of the hypereosinophilic syndrome (HES; over 1,500 cells per microliter) were found in 20 percent of EMF patients but in only 2 percent of the non-EMF cardiac patients and in 1 percent of the general medical patients. The prevalence of blood and stool parasites was identical in all groups and could not explain eosinophilia. More often than not the eosinophilic cells in EMF patients were abnormal.

HIV-Related Cardiomyopathy

People with AIDS have evidence of cardiac involvement at postmortem (40 percent) and by echocardiography (25 percent) (Fauci and Lane 2001). However, fewer than 10 percent ever experience symptoms. Cardiac involvement is the cause of death in only 1 to 2 percent of patients infected with HIV (Boon 2003). These figures may be higher in African populations, but good quality epidemiological data are lacking. The possibility of higher figures rests on the premises that nonischemic cardiomyopathy is more common in African populations than in Western countries and that the etiological factors that cause this high incidence of cardiomyopathy, be they nutritional deficiencies, genetic predispositions, or toxic factors, act synergistically with the effects of HIV infection on the heart.

HIV infection causes not only cardiomyopathy and heart failure but also CVA, pulmonary embolism, tuberculous pericarditis, marantic (nonbacterial) endocarditis, autonomic dysfunction, and proarrhythmic drug effects. In a recent review of 17 peer-reviewed publications covering January 1980 to February 2003 on cardiac involvement in HIV-infected people living in Africa, Magula and Mayosi (2003) showed that cardiac abnormalities are more common in HIV-infected people than in normal controls and that about half of hospitalized patients and a significant proportion of patients followed over several years develop cardiac abnormalities. The most common HIV-related cardiac abnormalities were cardiomyopathy and pericardial disease. Tuberculosis was the major cause of large pericardial effusion in Africa. HIV-related pericardial effusions are usually exudates and tend to occur in patients with advanced disease, with an annual incidence of 10 percent among people living with HIV and AIDS. They are an independent risk factor for early death, with median survival of less than six months after occurrence of the effusion.

Myocarditis was the most common pathological abnormality in HIV-associated cardiomyopathy, and nonviral opportunistic infections, such as toxoplasmosis and Cryptococcus, may account for up to 50 percent of such cases in Africa. Although the mechanisms involved in cardiomyopathy in people with HIV infection are poorly defined, a role for direct retroviral action or focal infiltration of activated immune cells, or both, has been postulated. Recent studies have demonstrated cardiac myocyte protein infiltration in AIDS-related cardiomyopathies, rather than focal immune cell lesions (Magula and Mayosi 2003). In Africa, however, other factors, such as nutritional deficiencies and the cardiotoxicity of antiretroviral medications, are associated with dilated cardiomyopathy in HIV-infected patients (Magula and Mayosi 2003). Long-term cardiac side effects of antiretroviral therapy are likely to become increasingly common in Africa as antiretroviral therapy becomes more readily available through national treatment programs, such as the Plan for the Comprehensive Treatment and Care of HIV and AIDS in South Africa (http://www.doh.gov.za), the WHO "3 by 5" Initiative (WHO 2004), and the President's Emergency Plan for AIDS Relief sponsored by the United States (IOM 2005). Most African programs, however, do not include protease inhibitors, responsible for much of the long-term cardiac toxicity, in their first regimen. Antiretroviral cardiac side effects may become apparent only in several years time as protease inhibitors come off patent and become affordable to national programs in Africa.

Sickle-Cell Disease

A study of 70 children between the ages of 3 and 16 years with homozygous sickle-cell anemia in Lomé, Togo, from January 1996 to April 1997 found that 26 percent had a normal heart, 66 percent had dilated cardiac cavities and a hypocontractile left ventricle, and 9 percent had nonobstructive cardiomyopathy, dilated cardiac cavities, and a hypocontractile left ventricle (Kokou et al. 1999). A study of the left ventricular systolic function of patients with sickle-cell anemia at the University College Hospital, Ibadan, Nigeria, revealed that although the left ventricular mass index was significantly larger in the patients than in the controls, there were no significant differences in the left ventricular systolic function at rest between patients with sickle-cell anemia and age- and sex-matched normal controls (Adebiyi, Falase, and Akenova 1999). The prominent cardiovascular abnormalities seen in patients with sickle-cell anemia, therefore, are most likely to have resulted from left ventricular diastolic dysfunction. Further studies are required to evaluate the left ventricular diastolic function in patients with sickle-cell anemia as well as their cardiac function during exercise and during episodes of crisis.

Congenital Heart Disease

Ventricular and atrial septal defect, Fallot's tetralogy, and patent ductus arteriosus were the most common congenital lesions in a Ghanaian study (Amoah 2000). The major cardiovascular disorders in children were congenital heart disease and RHD. Idiopathic cardiomyopathy was rare. In a study of 13,322 schoolchildren from Sahafa Town, Khartoum, Sudan, from 1986 to 1990, the prevalence of congenital heart disease was 2.0 per 1,000, with ventricular septal defect, atrial septal defect, patent ductus arteriosus, and Fallot's tetralogy making up 85 percent of the cases (Khalil et al. 1997). Patent ductus arteriosus and atrial septal defect were twice as common in females as in males. The prevalence rate was comparable to that of similar African countries but lower than European and North American rates.

Dysrhythmias

Atrial fibrillation is the most common cardiac arrhythmia in South Africa, often related to RHD, and is responsible for significant morbidity and mortality in the general population. The incidence of atrial fibrillation in South Africa is about 8 percent of the population 70 years and older. Atrial fibrillation affects more than 5 percent of the population over 65 and 10 percent of those over 80. The incidence is higher in patients with left ventricular hypertrophy and heart failure. Intraventricular malconductions seem to exhibit a prevalence in African populations similar to that in other parts of the world (Omotoso and Kane 2000).

Pericarditis

A study carried out from 1989 to 1996 in the Republic of Congo found that 4.9 percent of patients with cardiovascular disease had nonrheumatic pericarditis with effusion (Nkoua, Tsombou, and Bouramoue 1999). Twenty-two percent were HIV positive. The principal cause of the pericarditis was tuberculosis, which accounted for about a quarter of the patients, all of whom were HIV positive; all those with benign acute pericarditis were HIV negative; and all those with lymphocytic pericarditis were HIV positive. Of those affected by cardiac tamponade, just under a third were HIV positive. The mortality rate was 11.0 percent—9.9 percent among those who were HIV negative and 15.0 percent among those who were HIV positive. This study confirms the high rate of nonrheumatic pericardial effusion, the role of HIV infection, and the leading place of tuberculosis among causes. These findings corroborate those suggesting that the outcome of pericardial effusion associated with HIV infection can be cardiac tamponade (Nkoua, Tsombou, and Bouramoue 1999).

Determinants, Behaviors, and Risk Factors

In the past few decades appreciation of the importance of determinants and risk factors in the etiology of CVD has grown. Determinants are the ecological factors that provide the milieu in which a disease develops and need not be directly linked to the disease causally. Most people exposed to the determinant do not inevitably develop the disease. Genetic determinants provide the foundation on which behavioral, sociocultural, economic, and educational determinants build. As an example, the popular hypothesis that African people have a genetic predisposition for salt retention may be compounded in urban African cultures in which salt intake is high, thus causing hypertension and in part explaining the documented higher incidence of hypertension in urban than rural African societies (Steyn and Fourie 1991).

Risk factors arise from determinants and are directly linked to a disease in a causal fashion, although not everyone with the risk factor develops the disease. Risk factors include smoking, high blood pressure, malnutrition, obesity, hyperlipidemia, lack of physical exercise, and beta-hemolytic streptococcal infection. Many of the determinants of CVD are shared with cancer, diabetes, and chronic obstructive disease. Table 21.3 illustrates the relation between CVD determinants, risk factors, behaviors, and disease (Reddy 2004).

Table 21.3. The Relation between CVD, Risk Factors, Behaviors, and Determinants.

Table 21.3

The Relation between CVD, Risk Factors, Behaviors, and Determinants.

Coronary heart disease and stroke share the same risk factors, but their relative implication in the occurrence of these diseases is different. Since the middle of the twentieth century the prevalence of all risks factors for CVDs, except hyperlipidemia, has been increasing. Hyperlipidemia, although less prevalent than in developed countries, is found in patients with metabolic disorders and families with genetic susceptibility (Law 1998). Risk factors for CVD present in developed countries are the same in Sub-Saharan Africa, but their association and the possibly differing genetic susceptibilities may be responsible for the particular pattern of CVD in Africa.

A Tunisian population study estimated the prevalence of risk factors for CVD to be 19 percent for hypertension, 10 percent for diabetes, 28 percent for obesity, 36 percent for android obesity, and 21 percent for smoking (Ghanem and Fredj 1999). Total calorie intake was 2,483 kilocalories, comprised of 67 percent carbohydrates, 18 percent protein, and 15 percent fat. Among urban dwellers in Sub-Saharan Africa, intakes of food, especially fat, have risen, and intakes of high-fiber foods have fallen. The mean serum cholesterol level is significantly higher than that of rural populations living traditionally (Steyn and Fourie 1991). Obesity in females has risen enormously. The prevalence of hypertension exceeds that in developed countries. The same applies to the practice of smoking in males but not in females. The level of physical activity has fallen. Table 21.4 shows the relative prevalence of the most important risk factors for coronary heart disease in hospital patients.

Table 21.4. Risk Factors for CHD Reported from Hospital Patients.

Table 21.4

Risk Factors for CHD Reported from Hospital Patients.

Stroke and coronary heart disease occurs earlier in the lives of people in Africa, as in other low-income countries, than in the industrial world. Whereas CVDs are diseases of elderly people in developed countries, where they occur after the age of 60, they are preponderant in Africans even before the age of 40.

Hypertension

At the beginning of the twentieth century, high blood pressure was virtually nonexistent among indigenous Kenyans (Lore 1993) and Ugandans (Hutt 1990), but the reason may have been the lack of screening programs and access to care. From about 1975, high blood pressure became established in Cameroon, Côte d'Ivoire, Democratic Republic of Congo, Ghana, Kenya, Nigeria, and Uganda. As in developed countries, consumption of salt and alcohol, psychological stress, obesity, physical inactivity, and other dietary factors are thought to have played an important etiologic role in the genesis of primary hypertension in genetically predisposed individuals. Nevertheless, communities still exist in the Democratic Republic of Congo, Kenya, Nigeria, and the Kalahari Desert in which blood pressure is low and does not seem to rise with age. Rural-to-urban migration coupled with acculturation and modernization trends have some relation to the development of high blood pressure as observed in Kenyan and Ghanaian epidemiologic studies (table 21.5).

Table 21.5. Prevalence of Hypertension, by Country.

Table 21.5

Prevalence of Hypertension, by Country.

The prevalence of hypertension is particularly high in urban settings in Sub-Saharan Africa; between 8 and 25 percent of the adult population are affected, depending on what definition of hypertension is used. The two commonly used are the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure VI (JNC VI) definition (JNC 1997), which is a systolic pressure above 140 and diastolic pressure above 90 millimeters of mercury (mmHg), and a more conservative cutoff of 160 systolic pressure and 100 diastolic, as used in many African control programs. Over 80 percent of hypertensive patients in clinical practice have essential hypertension (that is, primary hypertension with no known cause), with most of the remainder having a renal origin for their hypertension (Akinkugbe 1976).

Before the latter half of the twentieth century most people in most Sub-Saharan Africa countries did not live beyond 40 years, the age at which hypertension becomes increasingly more prevalent. Some earlier researchers suggested that Africans did not show the characteristic increase in blood pressure with age (Shaper 1974), but this observation may have been due to deficiencies in the design of cohort studies.

So prevalent is hypertension today in Sub-Saharan Africa that hypertensive heart disease might in fact be the most common form of CVD in Africa. Hypertension is a risk factor for both stroke and IHD (Bradshaw et al. 2003). Left ventricular hypertrophy, congestive heart failure, and stroke are common in Africans with hypertension. There is little published information on formal programs addressing awareness, treatment, and control. Local, regional, and national surveys are required to provide epidemiological data necessary for informed decision making and policy setting on when and whom to treat in Africa (Kapuku, Mensah, and Cooper 1998; van der Sande et al. 2001).

There seem to be marked urban-rural differences in the prevalence of the disease (table 21.5). Prevalence levels are higher in South Africa among urban Zulu people than among their rural counterparts (Mokhobo 1976; Seedat, Seedat, and Hackland 1982) and among urban Xhosa people in Cape Town than their rural relatives in the Eastern Cape (Sever et al. 1980; Steyn et al. 1993). In Cameroon, age-adjusted rates of blood pressure in urban areas were greater than or equal to 160 mmHg systolic or 95 mmHg diastolic, and treatment of hypertension rose from 5 percent in rural areas to 17 percent in urban ones (Cruickshank et al. 2001).

Few studies from Africa have reported on hypertension treatment and control. In the Black Risk Factors Study (BRISK) study in urban black townships in the Cape peninsula of Cape Town, South Africa, 61 percent of those with hypertension (greater than or equal to 160 over 95 mmHg) were aware of their hypertension, and 48 percent were treated. In an urban population in the Democratic Republic of Congo only 31 percent of those with hypertension (blood pressure greater than or equal to 160 over 95 mmHg) were aware of their diagnosis; 13 percent were treated and 3 percent of those with hypertension had their disease controlled (M'Buyamba-Kabangu et al. 1986). Nigerian studies of hypertensive patients confirm that patients are unable to perceive changes in their blood pressure and should be taught to rely on regular blood pressure checks by their physician (Familoni and Ariba 2003).

In Western societies, such as the United States and the United Kingdom, the prevalence of hypertension and standardized mortality rates from stroke are higher for people of African origin than for whites (Cooper, Rotimi, Kaufman, et al. 1997). The same pattern is emerging in Sub-Saharan Africa. Thus in South Africa, age-adjusted hypertension prevalence and age-specific rates of death from stroke are higher among urban blacks than equivalent white populations (Opie and Steyn 1995). There is evidence that hypertension is an important cause of mortality in Sub-Saharan Africa. The Adult Morbidity and Mortality Project (AMMP 1997) showed that the probability of dying from an NCD (which is largely made up of stroke in Tanzania) between the ages of 15 and 60 years is more than six times higher in an urban area and between two and four times higher in two rural areas in Tanzania than in the United Kingdom (AMMP 1997). In the same study, NCD was the most common cause of death in the urban area and one of the rural areas for those over 60 years of age (figure 21.2).

Figure 21.2

Figure 21.2

Probability of Death by Broad Cause in Men between the Ages of 15 and 60 Years in Tanzania Source: AMPP 1997.

As in other parts of the world, the prevalence of hypertension in the Sub-Saharan Africa region has increased as a manifestation of the epidemiological transition (Omran 1983). This implies that, as elsewhere in the world, environmental factors related to urbanization and increasing affluence are important determinants of the disease.

As the number of fatalities from cardiovascular diseases declines in Western industrial nations, an opposite trend is observed in East Africa (Mbaya 1998). Interregional variations in the prevalence of vascular disorders have been attributed to socioeconomic, psychosocial, and heritable physiological parameters.

Among the Luo of Kenya, increasing blood pressure within months of migrating from the rural areas to the city has been recorded, with concomitant increases in their dietary sodium and declines in their dietary potassium (Poulter 1988; Poulter et al. 1984). A prospective cross-sectional study in rural Nigeria showed the prevalence of obesity to be 2 percent, with 1.2 percent in males and 3.2 percent in females (Okesina et al. 1999). High blood pressure, observed in 15.2 percent of the subjects, occurred more among males (19.1 percent) than females (10.3 percent). Malignant hypertension is common.

Hypertensive patients whose blood pressure fails to fall at night in the normal 24-hour rhythm (nondippers) have a higher incidence of cardiovascular complication, early glomerular failure, and microalbuminuria. A Nigerian study identified 28 percent nondippers, 57.1 percent of whom had microalbuminuria (Alebiosu et al. 2004).

As regards hypertension control, the guidelines of JNC VI may be more relevant to Sub-Saharan Africa than JNC VII because of the difficulty of effecting even moderate control of hypertension in Sub-Saharan Africa.

Hyperlipidemia

Hyperlipidemia is uncommon in Africa, being present mainly in patients with metabolic disorders (hypertriglyceridemia) or a family history of hypercholesterolemia. It is, however, present in 10 to 70 percent of patients with antecedent CHD or stroke. A study of black African patients admitted to a coronary care unit in Cape Town, South Africa, with acute ischemic syndromes and myocardial infarction revealed relative hyperlipidemia among the patients but not in the healthy controls (Mayosi et al. 1997).

Diabetes

Diabetes mellitus is a well-established risk factor for CVD (King, Aubert, and Herman 1998). The prevalence of type 2 diabetes in Africa is about 2.5 percent, ranging from 0.8 percent in rural Cameroon (Mbanya et al. 1997) to 13.5 percent in Mauritius (Dowse et al. 1990). Type 2 diabetes is more frequent in South Africa and North Africa than in central and West Africa, and it increases from rural to urban areas (Cooper, Rotimi, Kaufman, et al. 1997; King and Zimmet 1988). The World Bank ranks these countries as upper-middle-income countries, and they are further along the epidemiological transition than the low-income countries of Sub-Saharan Africa (table 21.6).

Table 21.6. Prevalence of Diabetes, by Country.

Table 21.6

Prevalence of Diabetes, by Country.

Tobacco Smoking and Alcohol Consumption

Tobacco consumption in South Africa has declined since 1994 due to stringent antitobacco legislation and hikes in excise duty, resulting in 25 percent reductions in both the number of people smoking and overall tobacco consumption (Reddy 1997; Steyn 1998) (see table 21.7). Alcohol consumption, however, is relatively frequent in Africa. The types of alcohol consumed include wine, beer, and locally made beverages. Alcohol has been implicated in the development of hypertension, CHD, stroke, and heart failure (table 21.8).

Table 21.7. Prevalence of Tobacco Smoking, by Country.

Table 21.7

Prevalence of Tobacco Smoking, by Country.

Table 21.8. Prevalence of Alcohol Consumption, by Country.

Table 21.8

Prevalence of Alcohol Consumption, by Country.

Lack of Physical Activity

Physical activity is more prevalent in rural than urban regions of Africa, and that partly explains the higher prevalence of obesity in urban areas. The prevalence of sedentary lifestyles in Cape Town, South Africa, among individuals 30 years of age and above was 39 percent for men and 44 percent for women (Levitt et al. 1993). Twenty-two percent of men and 52 percent of women in urban Tanzania (Edwards et al. 2000) had low levels of physical activity. Also, 10 percent of men and 15 percent of women in rural areas indicated low physical activity during the same study.

Obesity

Obesity is increasing in prevalence in Sub-Saharan Africa; particularly among urban women (tables 21.9 and 21.10). However, the value of the waist-hip ratio has never been properly validated in large population-based studies in Sub-Saharan Africa in regard to their predictive value for cardiovascular outcomes. The same holds true for waist circumference of greater than 88 centimeters for females and 102 centimeters for males.

Table 21.9. Prevalence of Obesity, by Country.

Table 21.9

Prevalence of Obesity, by Country.

Table 21.10. Prevalence of Obesity in Women Age 15 to 49 Years, by Country.

Table 21.10

Prevalence of Obesity in Women Age 15 to 49 Years, by Country.

Genetic Determinants

The renin-angiotensin system and associated gene polymorphisms may be important in predicting cardiovascular events, but the association is likely to be weak, as shown in one study of myocardial infarction in young South African Indians (Ranjith et al. 2004).

Prevention, Rehabilitation, and Cure of Cardiovascular Disease

Traditionally, interventions have focused on altering risk factors by, for example, eradicating streptococcal infection using antibiotics in order to prevent rheumatic fever and subsequent RHD. The health promotion approach, however, teaches that to be fully effective in curing, ameliorating, or preventing a disease, one must understand how the determinants give rise to a disease within particular settings. One can then develop determinant-based interventions. Thus, for example, rheumatic fever typically develops in situations of poverty and overcrowding, where children are malnourished, immunocompromised, and susceptible to bacterial infection. An intervention that focuses on providing penicillin for those children with streptococcal sore throat will not be fully effective in eradicating the disease. The determinants of the disease must also be dealt with by educating the caregiver to appreciate the need for prompt treatment of sore throats, educating health professionals to take a throat swab before starting antibiotic treatment, providing child support grants to caregivers so that they can buy food for the malnourished child, alleviating overcrowding so that the sick child does not sleep six to a bed with his or her siblings, thus spreading infection, and so on.

Health promotion also teaches the importance of the "settings approach" to disease prevention and control. It appreciates that the bulk of disease management does not take place in the hospital or clinic but in the home, the school, and the workplace. Understanding the etiology, natural history, and management paradigms of the disease within these settings is therefore crucial to developing prevention, rehabilitation, and cure programs.

These interventions may be tailored for the population, such as screening schoolchildren by taking throat swabs for beta-hemolytic streptococcus after an outbreak of rheumatic fever in a school or treating an infected child with penicillin for a streptococcal sore throat. Primary prevention may include the prevention and treatment of streptococcal infection by providing school feeding programs for malnourished children and providing penicillin to treat sore throats or training health personnel in the diagnosis of the condition and educating the caregiver. Secondary prevention is treating with penicillin for several years after an attack of rheumatic fever in order to prevent rheumatic heart disease; and tertiary prevention could involve treating the valvular cardiac disease of RHD symptomatically with diuretics and digoxin, curatively with balloon valvuloplasty or cardiac surgery.

A modern understanding of disease management emphasizes the importance of analyses of the cost-effectiveness of disease interventions in order to build sustainable systems for disease control. This is important for developed countries as well as for developing countries. It is particularly critical for the prevention and control of cardiovascular disease, for which secondary and tertiary interventions are often extremely expensive and require high-grade technical skills to administer. A difficult tradeoff has to be made in such CVD control programs between the different interventions, and this is best done rationally rather than emotionally. The tradeoff may be between providing antibiotics to prevent rheumatic fever versus providing surgery to babies with congenital heart disease, a difficult choice to make. The former intervention, however, may be far more cost-effective in the long run.

It is extremely difficult for policy makers and health planners to articulate and make these choices, as they often come with considerable political as well as emotional cost. Often the hard choice is masked under a "waiting list" on which children may die without an overt decision having been made to deny them lifesaving interventions. In Sub-Saharan Africa there often is no choice to make because the suffering and dying patients never even reach the clinic to demand treatment, or the facilities and surgeons to provide the surgery are nonexistent.

Impact on the Health Care System in Africa and Strategies for Control and Prevention

Options to improve monitoring of CVD morbidity and risk-factor levels include establishing community registries of stroke and repeatedly examining representative population samples. Nationwide vital registration to monitor CVD mortality would be desirable but appears not to be feasible at present, and maintaining a sample registration system would be prohibitively expensive.

In spite of the current low prevalence of hypertension in some countries, the total number of people with hypertension in the developing world is high, and a cost analysis of possible antihypertensive drug treatment indicates that developing countries cannot afford the same treatment as developed countries (Seedat 2000). Only 20 percent of the hypertension in the United States is under control, whereas in Africa only 5 to 10 percent is controlled at a blood pressure of less than 140 over 90 mmHg (Pretoria Department of Health 2002).

It is claimed that black patients respond well to thiazide diuretics, calcium channel blockers, and vasodilators such as alpha-blockers, hydralazine, and reserpine, and respond poorly to beta-blockers, angiotensin-converting enzyme inhibitors, and angiotensin II receptor antagonists unless they are combined with a diuretic. This is increasingly being brought into doubt, however. Comprehensive cardiovascular disease research programs in Africa are needed, as social, economic, and cultural factors impair control of hypertension in developing countries. Hypertension control is ideally suited to the initial component of an integrated CVD control program. Primary prevention, through a program focused on lifestyle should be synergistically linked to cost-effective methods of detection and management. The existing health care infrastructure needs to be oriented to meet the emerging challenge of CVD while empowering the community through health education.

The lipid cardiovascular risk-factor profile of African populations continues to be relatively benign, with mean total cholesterol, LDL cholesterol and HDL cholesterol, and median triglyceride levels in the "low risk" ranges, even among cohorts with established CVD. The other major risk factors, however, are significantly elevated in urban populations, particularly prevalent hypertension, increasing obesity, and type 2 diabetes mellitus, as well as growing rates of tobacco use. Furthermore, the prevalence of risk factors has risen in both urban and rural areas. A 1998 study carried out by the WHO in Tanzania found that hypercholesterolemia (total cholesterol greater than 5.2 millimeters molar per liter) was present in 21.8 percent of men and 54 percent of women; that measured weight, body mass index (BMI), and prevalence of obesity (BMI greater than or equal to 30 kilograms per square meter) had increased significantly to 22.8 percent among women in urban Dar es Salaam; and that the overall prevalence of hypertension (blood pressure higher than 160 over 95 mmHg or antihypertensive drug use) was 41.1 percent (Njelekela et al. 2001).

These classical risk factors operate in much the same way as in northern European populations with regard to being predictive of CVD (Kruger, Venter, and Vorster 2001; Yusuf et al. 2004). To date no evidence has been found that Africans have esoteric, genetically determined risk factors that differ from other populations in the world; nor do they appear to have special genetic traits that protect them from heart disease. It seems likely that the continuing socioeconomic advance in many African countries will be accompanied by the attendant increases in CVD that are seen in epidemiological transitions across the world. The challenge is to introduce primary and secondary prevention measures now, before the epidemic of CVD accelerates, particularly as such strategies may be more cost-effective than angioplasty and cardiac surgery in the cash-strapped economies of Sub-Saharan Africa.

Up to 22 percent of premature all-cause mortality and 45 percent of stroke mortality could be reduced by appropriate detection and treatment (Yusuf et al. 2004). Cheap, effective therapy is available. With mortality risk now higher from NCDs than from communicable diseases in Sub-Saharan Africa and elsewhere, systematic measurement, detection, and genuine control of hypertension once treated can go hand-in-hand with other adult health programs in primary care. In many African countries undernutrition coexists with obesity in the same communities, demonstrating a double burden of disease, such as in The Gambia, where a 1996 community-based survey demonstrated a prevalence of undernutrition (BMI less than 18 kilograms per square meter) of 8 percent, whereas prevalence of obesity (BMI greater than or equal to 30 kilograms per square meter) was 4 percent. However, obesity was higher (32.6 percent) among urban women 35 years or older (van der Sande et al. 2001). Furthermore, CVD risk factors tend to cluster, with the potential for synergistic effects, as has been described in other populations in the world (Kruger, Venter, and Vorster 2001). Differential interventions should focus on high-risk groups, and prevention needs a multisectoral, health promotion approach.

A suitable strategy to adopt in the prevention and control of NCDs is the WHO Global Strategy for Noncommunicable Diseases, whose principal objectives are to do the following:

  • Map the emerging epidemics of NCD and analyze their determinants.
  • Reduce the levels of exposure of populations to common risk factors and their determinants.
  • Develop norms and guidelines for effective interventions.

NCDs, including cardiovascular and cerebrovascular disease, pulmonary diseases, liver disease, cancer, diabetes, osteoporosis, and trauma, constitute the major cause of death in developed countries and are predictably emerging as significant threats to health in countries at intermediate stages of the epidemiological transition (Yusuf et al. 2004). Interventions could be designed based on the philosophy that diseases with common risk factors, such as smoking, increased fat and salt in the diet, alcohol abuse, and so on, require common preventive strategies.

Screening programs to detect hypertension in the community may be appropriate, as the disease does not become clinically manifest until it causes end organ damage, such as heart failure, heart attack, stroke, and kidney failure. Such measures would be subject to the constraints of available resources, however; and an approach that targets high-risk patients, that is, those who present with other related conditions or with multiple risk factors, may be more feasible than populationwide screening in poorer African countries (WHO 2002).

Health systems in developing countries will need to be drastically improved to deal with the burden, as they often suffer from inefficient allocation of resources and management of services. Better management must be based on both the high-risk-behaviors approach, such as detection and management of obesity, hypertension, and diabetes at the primary health care level, and the populationwide approach, such as education through the mass media and schools. Integration of the package of CVD prevention and control within the programs of ministries of health will be needed.

Increasing availability of drugs and diagnostics is a major issue in Africa, as it was for HIV/AIDS and tuberculosis. Local manufacture of off-patent CVD drugs may improve access as well as stimulate the economy, as proposed in the Initiative for Pharmaceutical Technology Transfer of South Africa, a program of the New Partnership for Africa's Development.

Health technology for management of these CVDs will need to be appropriate, affordable, and sustainable and not simply imported from the West. The detection, prevention, and control of CVD in women is a major issue in Sub-Saharan Africa, where women may suffer inferior diagnosis of CVD and limited access to care because of adverse gender-power relations between men and women.

CVD control in Africa will probably not reach a high level of adequacy for a few decades to come, given the scant human, financial, and infrastructural resources in its countries. However, those countries cannot ignore the problem if they hold fast to the dictum of "health as a human right." They will, however, have to carefully categorize and prioritize their public health expenditure on the prevention and control of CVD. The experience of developed countries, who are further on in the course of their "epidemiological transition," suggests that primary prevention of CVD now is likely to be more cost-effective than acute care for affected patients in 20 years. In the United States, for example, the direct costs of CVD are estimated to account for 2 percent of the gross domestic product. In Canada, CVD accounts for 21 percent of total disease-classifiable costs of illness. The data for other chronic diseases in developing countries suggest that these scales of health care costs are likely to be similar. As an example, in India, the annual cost of drugs for a patient with type 2 diabetes mellitus is US$70, considerably more than the annual per capita expenditure on health care in that country. In Tanzania, diabetes care swallows up 8.1 percent of the health care budget (http://www.ichealth.org).

The costs of intersectoral, primary preventive measures to control CVD are likely to be much lower than those for acute, secondary care. As an example, the cost-effectiveness of introducing antitobacco legislation, or limiting the quantities of salt permitted in processed food, is likely to be substantially higher than building coronary care units. The evidence from developed countries since 1990 suggests that most of the decline in CVD mortality in these countries has resulted from better secondary care for CVD, but the relative cost per life saved is still high, too high for health systems in developing countries to cope with. Developed countries faced the peak in their incidence of CVD when they were already wealthy and had the resources to cope. Thus, the stratagems adopted by developing countries are likely to be different. In secondary care, African countries of the south will need to develop essential vascular packages, such as aspirin and beta-blockers for patients with angina pectoris. The data are scanty and there is a dire need for more health economics research.

Development of a global program to provide access to CVD drugs, similar to the "3 by 5" Initiative of the WHO for antiretroviral drugs, is unlikely, because cardiovascular deaths do not have the same emotive power as AIDS deaths. Yet CVD deaths are often sudden, striking down victims in their most productive years and resulting in deep emotional and economic shock for their families. For survivors, the years lived with disability, such as heart failure or hemiplegia, are often traumatic and expensive because of health care costs and lost productivity. The prognosis for living with heart failure is like that for someone living with HIV/AIDS on antiretrovirals; the annual mortality is 5 to 15 percent. Perhaps the health systems being set up in African countries for provision of antiretroviral drugs and comprehensive AIDS care could have the beneficial side effect of providing systems and personnel for CVD surveillance and care.

In many African countries medicinal plants are used to treat cardiovascular complaints (Diallo et al. 1999). If these are truly effective, it could in part explain the low prevalence of CVD (and cancer) in rural African populations. Indigenous knowledge systems should be researched, in order to determine whether to popularize natural medicines for the prevention and cure of CVD. Cardiovascular disorders currently receive little or no attention in most African countries (Muna 1993b). Projections based on recent studies suggest that the management of these disorders will represent a major challenge for the overextended and shrinking health budgets of these poor nations in the near future. Given the prevalence of such common cardiovascular conditions as hypertension, which in some cases can be 25 percent or higher, treatment is beyond the budgetary possibilities of any of the African countries. Other conditions, including infections involving the heart and related structures, rheumatic fever and its complications, cardiomyopathies, and congenital heart disease, are also common. Recent trends suggest that ischemic heart disease may be less uncommon than was previously thought. Health planners and policy makers must be educated on the crucial role of health research in general, and cardiovascular disorders research in particular, as a basis for formulating a rational health care policy and making managerial decisions. The need for training and funding, and especially the leadership required to develop and sustain research activity, will require a multidisciplinary, multidirectional, collaborative approach at national and international levels, as well as firm local commitment. As is the case for most other important health problems, cardiovascular disorders are rapidly becoming a global issue and should be recognized as such.

Following the guidelines of JNC VI in the screening, detection, and treatment of all hypertensive patients is beyond the health budgets of most African countries (Gaziano and Opie 2001). Most countries, therefore, adopt an opportunistic approach to the identification of patients with hypertension and aim for significantly higher target blood pressures than those recommended. The result is that considerable numbers of patients continue to suffer hypertension-related strokes leading to disability or death. This inadequate detection and treatment of hypertension is the most likely explanation for the high proportion of hemorrhagic strokes in African populations.

The major challenges in the management of hypertension are therefore twofold. First is to develop cost-effective, population-based, health promotive strategies for primary prevention, and secondary amelioration of hypertension. The second challenge is to lower the costs of treatments through strategies such as the local manufacture of antihypertensive drugs that have come off patent (IPTT 2003). These are also probably the principal challenges in the management of cardiovascular disease in Africa, as hypertensive stroke is the leading cause of cardiovascular death and disability in Africa. Research is under way to develop these prevention and control strategies (http://www.ichealth.org).

Research continues into which of the two approaches to hypertensive control is most cost-effective: treating hypertension according to the absolute risk for CVD or following an arbitrary blood pressure target. The former is likely to be more cost-effective, but more research is still needed to settle the issue.

The prevention and treatment of CVDs has become a priority for some multilateral agencies. The WHO is active in promoting prevention strategies, including tobacco control and hypertension treatment. The World Bank has funded cardiovascular control initiatives in a few countries through its loans program. However, among other lenders and donors of funds for health care, such as the Asian Development Bank and most bilateral donor agencies, CVD remains a low priority (http://www.ichealth.org).

Conclusion

CHD and strokes share common determinants and risk factors and are more common in urban than rural areas. Any suggestion that people of black African descent are in some way immune from CVD has been dispelled by well-documented evidence from, among other countries, Cameroon, Caribbean countries, Mauritius, the Seychelles, South Africa, Tanzania, and the United States. In such countries CVD already accounts for between 15 and 40 percent of all deaths.

Data on the burden of cardiovascular disease for most African countries are, however, scanty. The estimations made in the Global Burden of Disease Study for CVD in 1990 in Africa relied on data from only 2 percent of the 700 million inhabitants of Africa (Murray and Lopez 1996). Still, studies do suggest that the prevalence of risk factors for CVD, and the behavioral, socioeconomic, and demographic determinants that underlie these risk factors, are increasing in Africa, despite the persistence of an appalling burden of communicable disease and diseases of poverty. Furthermore, the prevailing pattern of past decades, when CVD in Africa was predominantly RHD, hypertensive heart disease, stroke, and dilated cardiomyopathy, is now beginning to change, with an increasing proportion of morbidity and mortality due to ischemic heart disease.

It is probably cheaper and more effective to take population-based measures to prevent heart disease and stroke than it is to treat the people with surgery and drugs once CVD is established. RHD and heart failure also have highly effective primary and secondary interventions that can be readily applied. The time to act in prevention and control of CVD is now.

References

  1. Adebiyi A. A., Falase A. O., Akenova Y. A. Left Ventricular Systolic Function of Nigerians with Sickle Cell Anaemia. Annals of Oncology. 1999;24(98):27–32.
  2. Akinkugbe O. O. Epidemiology of Hypertension and Stroke in Africa. Mongor Citation. 1976;29:28–42.
  3. Alebiosu C. O., Odusan B., Familoni O. B., Jaiyesimi A. E. A. Pattern of Occurrence of Microalbuminuria among Dippers and Non-Dippers (Essential Hypertensives) in a Nigerian University Teaching Hospital. Cardiovascular Journal of South Africa. 2004;15:9–12. [PubMed: 14997231]
  4. AMMP (Adult Mortality and Morbidity Project). 1997. Policy Implications of Adult Mortality and Morbidity. End of Phase I Report. Dar es Salaam: Department for International Development.
  5. Amoah A. G. B. Spectrum of Cardiovascular Disorders in a National Referral Centre, Ghana. East African Medical Journal. 2000;77:648–53.
  6. Anabwani G. M., Bonhoeffer P. Prevalence of Heart Disease in School Children in Rural Kenya Using Colour-Flow Echocardiography. East African Medical Journal. 1996;73:215–17. [PubMed: 8706601]
  7. Astagneau P., Lang T., Delarocque E., Jeannee E., Salem G. Arterial Hypertension in Urban Africa: An Epidemiological Study on a Representative Sample of Dakar Inhabitants in Senegal. Journal of Hypertension. 1992;10(9):1095–1101. [PubMed: 1328370]
  8. Beaglehole R., Yach D. Globalisation and the Prevention and Control of Non-Communicable Disease: The Neglected Chronic Diseases of Adults. Lancet. 2003;362:903–8. [PubMed: 13678979]
  9. Berrios X., Koponen T., Huiguang T., Khaltaev N., Puska P., Nissinen A. Distribution and Prevalence of Major Risk Factors of Noncommunicable Diseases in Selected Countries: The WHO Inter-Health Programme. Bulletin of the World Health Organization. 1997;75:99–108. [PMC free article: PMC2486940] [PubMed: 9185361]
  10. Bertrand E. Coronary Disease in Black Africans: Epidemiology, Risk Factors, Clinical Symptomatology and Coronary Evolution. Académie Nationale de Médecine Bulletin. 1992;176(3):311–23. ; discussion 323–26. [PubMed: 1504858]
  11. Betre M., Kebede D., Kassaye M. Modifiable Risk Factors for Coronary Heart Disease among Young People in Addis Ababa. East African Medical Journal. 1997;74:376–81. [PubMed: 9487400]
  12. Boon, N. 2003. "Cardiac Disease in HIV Infection." In Oxford Textbook of Medicine, ed. D. A. Warrell, T. M. Cox, and J. D. Firth. Oxford: Oxford University Press.
  13. Bovet P. The Epidemiologic Transition to Chronic Diseases in Developing Countries: Cardiovascular Mortality, Morbidity, and Risk Factors in Seychelles (Indian Ocean). Investigators of the Seychelles Heart Study. Sozial- und Praventivmedizin. 1995;40(1):35–43. [PubMed: 7900434]
  14. Bovet P., Ross A. G., Gervasoni J. P., Mkamba M., Mtasiwa D. M., Lengeler C., Whiting D., Paccaud F. Distribution of Blood Pressure, Body Mass Index and Smoking Habits in the Urban Population of Dar es Salaam, Tanzania, and Associations with Socioeconomic Status. International Journal of Epidemiology. 2002;31(1):240–47. [PubMed: 11914327]
  15. Bradshaw, D., D. Bourne, M. Schneider, and R. Sayed. 1995. "Mortality Patterns of Chronic Diseases of Lifestyle in South Africa." In Chronic Diseases of Lifestyle in South Africa, ed. J. Fourie, 5–31. Cape Town: South African Medical Research Council.
  16. Bradshaw, D., P. Groenewald, R. Laubscher, N. Nannan, B. Nojilana, R. Norman, D. Pieterse, and M. Schneider. 2003. Initial Burden of Disease Estimates for South Africa, 2000. Cape Town: South African Medical Research Council.
  17. Ceesay M. M., Morgan M. W., Kamanda M. O., Willoughby V. R., Lisk D. R. Prevalence of Diabetes in Rural and Urban Populations in Southern Sierra Leone: A Preliminary Survey. Tropical Medicine and International Health. 1997;2(3):272–77. [PubMed: 9491107]
  18. Chinyadza E., Moyo I. M., Katsumbe T. M., Chisvo D., Mahari M., Cock D. E., Mbengeranwa O. L. Alcohol Problems among Patients Attending Five Primary Health Care Clinics in Harare City. Central African Journal of Medicine. 1993;39:26–32. [PubMed: 8261500]
  19. Cooper R. S., Rotimi C. N., Ataman S., McGee D., Osotimehin B., Kadiri S., Muna W. et al. The Prevalence of Hypertension in Seven Populations of West African Origin. American Journal of Public Health. 1997;87(2):160–68. [PMC free article: PMC1380786] [PubMed: 9103091]
  20. Cooper R. S., Rotimi C. N., Kaufman J. S., Owoaje E. E., Fraser H., Forrester T., Wilks R., Riste L. K., Cruickshank J. K. Prevalence of NIDDM among Populations of the African Diaspora. Diabetes Care. 1997;20:343–48. [PubMed: 9051385]
  21. Cruickshank J. K., Mbanya J. C., Wilks R., Balkau B., Forrester T., Anderson S. G., Mennen L., Forhan A., Riste L., McFarlane-Anderson N. Hypertension in Four African-Origin Populations: Current `Rule of Halves,' Quality of Blood Pressure Control and Attributable Risk of Cardiovascular Disease. Journal of Hypertension. 2001;19:41–46. [PubMed: 11204303]
  22. Davidson J. C. The Incidence of Diabetes in Nyasaland. Central African Journal of Medicine. 1963;9:92–94. [PubMed: 14025369]
  23. Davies J. N. P. Endocardial Fibrosis in Africans. East African Medical Journal. 1948;25:10. [PubMed: 18884861]
  24. Diallo D., Hveem B., Mahmoud M. A., Berge G., Paulsen B. S., Maiga A. An Ethnobotanical Survey of Herbal Drugs of Gourma District, Mali. Pharmaceutical Biology. 1999;37(1):80–91.
  25. Dowse G. K., Gareeboo H., Zimmet P. Z., Alberti K. G., Tuomilehto J., Fareed D., Brissonnette L. G., Finch C. F. High Prevalence of NIDDM and Impaired Glucose Tolerance in Indian, Creole, and Chinese Mauritians. Mauritius Noncommunicable Disease Study Group. Diabetes. 1990;39:390–96. [PubMed: 2307296]
  26. Drury R. A. B. The Mortality of Elderly Ugandans. Tropical and Geographical Medicine. 1972;24:385–92. [PubMed: 4648651]
  27. Edington G. M. Cardiovascular Disease as a Cause of Death in Gold Coast Africa. Transactions of the Royal Society of Tropical Medicine and Hygiene. 1954;48:419–25. [PubMed: 13216946]
  28. Edwards R., Unwin N., Mugusi F., Whiting D., Rashid S., Kissima J., Aspray T. J., Alberti K. G. Hypertension Prevalence and Care in an Urban and Rural Area of Tanzania. Journal of Hypertension. 2000;18(2):145–52. [PubMed: 10694181]
  29. Ekra A., Bertrand E. Rheumatic Heart Disease in Africa. World Health Forum. 1992;13(4):331–33. [PubMed: 1345419]
  30. Erasmus R. T., Fakeye T., Olukoga O., Okesina A. B., Ebomoyi E., Adeleye M., Arije A. Prevalence of Diabetes Mellitus in a Nigerian Population. Transactions of the Royal Society of Tropical Medicine and Hygiene. 1989;83(3):417–18. [PubMed: 2617592]
  31. Ezenwaka C. E., Akani A. O., Akanji B. O., Unwin N. C., Adejuwon C. A. The Prevalence of Insulin Resistance and Other Cardiovascular Disease Risk Factors in Healthy Elderly Southwestern Nigerians. Atherosclerosis. 1997;128(2):201–11. [PubMed: 9050777]
  32. Familoni O. B., Ariba A. J. Ability of Nigerian Hypertensive Patients to Perceive Changes in Their Blood Pressure. Cardiovascular Journal of South Africa. 2003;14:195–98. [PubMed: 14532961]
  33. Fauci A. S., Lane H. C. Human Immunodeficiency Virus (HIV) Disease: AIDS and Related Disorders. In Harrison's Principles of Internal Medicine, 15th ed. 2001;1:884. New York: McGraw-Hill.
  34. Fisch A., Pichard E., Prazuck T., Leblanc H., Sidibe Y., Brucker G. Prevalence and Risk Factors of Diabetes Mellitus in the Rural Region of Mali (West Africa): A Practical Approach. Diabetologia. 1987;30:859–62. [PubMed: 3446552]
  35. Gaziano T. A., Opie L. Cost-Effective Analysis of Proposed Hypertension Guidelines in South Africa; Beta-Blocker Therapy for Hypertension: Hypertension in South Africa and Efficacy of First Line Therapy. Abstract. Cardiovascular Journal of Southern Africa. 2001;12(4):223.
  36. Ghanem H., Fredj A. H. Eating Habits and Cardiovascular Risk Factors. Presse Medicale. 1999;28(19):1005–8. [PubMed: 10379346]
  37. Hale L. A., Fritz V. U., Eales C. J. Do Stroke Patients Realise That a Consequence of Hypertension Is Stroke? South African Medical Journal. 1998;88(4):451–54. [PubMed: 9594990]
  38. Hutt, M. S. R. 1990. "Cancer and Cardiovascular Diseases." In Disease and Mortality in Sub-Saharan Africa, ed. D. T. Jamieson and R. G. Feachem. New York: Oxford University Press.
  39. Hutt M. S. R., Coles R. Postmortem Findings in Hypertensive Subjects in Kampala, Uganda. East African Medical Journal. 1969;46:342–58. [PubMed: 5345973]
  40. IOM (Institute of Medicine). 2005. Scaling Up Treatment for the Global AIDS Pandemic. Washington, DC: National Academies Press.
  41. IPTT (Initiative on Pharmaceutical Technology Transfer). 2003. "A New Partnership for Africa's Development (NEPAD) Project for the Local Manufacture of Pharmaceuticals in Africa." http://www​.iptt.net.
  42. Isezuo A. S., Omotoso A. B. O., Gaye A., Corrah T., Araoye M. A. One-Year Survival among Sub-Saharan Africans with Hypertensive Heart Failure. Cardiologie Tropicale. 2000;26(103):57–60.
  43. JNC (Joint National Committee). The Sixth Report of the National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure (JNC VI) Archives of Internal Medicine. 1997;157:2413–46. [PubMed: 9385294]
  44. Kadiri S., Salako B. L. Cardiovascular Risk Factors in Middle Aged Nigerians. East African Medical Journal. 1997;74(5):303–6. [PubMed: 9337008]
  45. Kapuku G. K., Mensah G. A., Cooper R. S. Hypertension in Africa. Africa Health. 1998;20(2):6–8.
  46. Khalil S. I., Gharieb K., El-Haj M., Khalil M., Hakiem S. Prevalence of Congenital Heart Disease among Schoolchildren of Sahafa Town, Sudan. Eastern Mediterranean Health Journal. 1997;3(1):24–28.
  47. Kimbally-Kaky G., Bouramoue C. Profile and Prospects of Patients from Congo with Cardiac Insufficiency: Report of 743 Cases. Médecine d'Afrique Noire. 2000;47(4):197–203.
  48. King H., Aubert R. E., Herman W. H. Global Burden of Diabetes, 1995–2025: Prevalence, Numerical Estimates, and Projections. Diabetes Care. 1998;21:1414–31. [PubMed: 9727886]
  49. King H., Zimmet P. Trends in the Prevalence and Incidence of Diabetes: Non-Insulin-Dependent Diabetes Mellitus. World Health Statistics Quarterly. 1988;41(34):190–96. [PubMed: 2466380]
  50. Kokou O. I., Agbere A. D., Atakoumi D. Y., Gbadoe A. D., Tsolenyanu E., Djossou-Agbodjan O., Baeta S., Tatagan-Agbi K., Assimadi K. Cardiac Repercussions of Sickle Cell Anaemia in Children in Lomé: Report of 70 Cases. Archives de Pediatrie. 1999;6(10):1134. [PubMed: 10544798]
  51. Kotto R. M., Bouelet B. A. Cardiovascular Diseases in Adults in Douala (Cameroon) Cardiologie Tropicale. 2000;26(103):61–64.
  52. Kruger H. S., Venter C. S., Vorster H. H. Obesity in African Women in the North West Province, South Africa Is Associated with an Increased Risk of Non-Communicable Diseases: The THUSA Study. Transition and Health during Urbanisation of South Africans. British Journal of Nutrition. 2001;86(6):733–40. [PubMed: 11749683]
  53. Law C. M., Egger P., Dada O., Delgado H., Kylberg E., Lavin P., Tang G. H., Hertzen H., Shiell A. W., Barker D. J. Body Size at Birth and Blood Pressure among Children in Developing Countries. International Journal of Epidemiology. 2001;30(1):52–59. [PubMed: 11171856]
  54. Law, M. 1998. "Lipids and Cardiovascular Disease." In Evidence Based Cardiology, ed. S. Yusuf, J. A. Cairns, A. J. Camm, E. L. Falen, and B. J. Gersh, 191–205. London: British Medical Journal Books.
  55. Lawlor D. A., Davey Smith G., Ebrahim S. Birth Weight of Offspring and Insulin Resistance in Late Adulthood: Cross Sectional Survey. British Medical Journal. 2002;325(7360):359. [PMC free article: PMC117884] [PubMed: 12183306]
  56. Levitt N. S., Katzenellenbogen J. M., Bradshaw D., Hoffman M. N., Bonnici F. The Prevalence and Identification of Risk Factors for NIDDM in Urban Africans in Cape Town, South Africa. Diabetes Care. 1993;16:601–7. [PubMed: 8462387]
  57. Lodenyo H. A., McLigeyo S. O., Ogola E. N. Cardiovascular Disease in Elderly In-Patients at the Kenyatta National Hospital, Nairobi, Kenya. East African Medical Journal. 1997;74:647–51. [PubMed: 9529748]
  58. Lore W. Epidemiology of Cardiovascular Diseases in Africa with Special Reference to Kenya: An Overview. East African Medical Journal. 1993;70:357–61. [PubMed: 8261957]
  59. Magula N. P., Mayosi B. M. Cardiac Involvement in HIV-Infected People Living in Africa: A Review. Cardiovascular Journal of South Africa. 2003;14:231–37. [PubMed: 14610610]
  60. Martorell R., Khan L. K., Hughes M. L., Grummer-Strawn L. M. Obesity in Women from Developing Countries. European Journal of Clinical Nutrition. 2000;54(3):247–52. [PubMed: 10713748]
  61. Mayanja-Kizza H., Gerwing E., Rutakingirwa M., Mugerwa R., Freers J. Tropical Endomyocardial Fibrosis in Uganda: The Tribal and Geographic Distribution, and the Association with Eosinophilia. Cardiologie Tropicale. 2000;26(103):45–48.
  62. Matenga J. Stroke Incidence Rates among Black Residents of Harare—A Prospective Community-Based Study. South African Medical Journal. 1997;87(5):606–9. [PubMed: 9254819]
  63. Mayosi B. M., Marais A. D., Mbewu A. D., Byrnes P. Risk Factor Profile of Black Patients with Acute Coronary Syndromes. Canadian Journal of Cardiology. 1997;13:242B.
  64. Mbanya J. C., Minkoulou E., Salah J., Balkau B. The Prevalence of Hypertension in Rural and Urban Cameroon. International Journal of Epidemiology. 1998;27(2):181–85. [PubMed: 9602396]
  65. Mbanya J. C., Ngogang J., Salah J. N., Minkoulou E., Balkau B. Prevalence of NIDDM and Impaired Glucose Tolerance in a Rural and an Urban Population in Cameroon. Diabetologia. 1997;40(7):824–29. [PubMed: 9243104]
  66. Mbaya V. B. Hypertension in East Africans and Others of African Descent: A Review. East African Medical Journal. 1998;75:300–03. [PubMed: 9747003]
  67. Mbewu, A. D. 1998. "Can Developing Country Systems Cope with the Epidemics of Cardiovascular Disease?" Paper presented at the Heart Health Conference, New Delhi, India.
  68. M'Buyamba-Kabangu J., Fagard R., Lijnen P., Staessen J., Ditu M., Tshiani K., Amery A. Epidemiological Study of Blood Pressure and Hypertension in a Sample of Urban Bantu of Zaire. Journal of Hypertension. 1986;4:485–91. [PubMed: 3772101]
  69. Mendez G. F., Cowie M. R. The Epidemiological Features of Heart Failure in Developing Countries: A Review of the Literature. International Journal of Cardiology. 2001;80(23):213–19. [PubMed: 11578717]
  70. Metcalf C. A., Hoffman M. N., Steyn K., Katzenellenbogen J. M., Fourie J. M. Design and Baseline Characteristics of a Hypertension Intervention Program in a South African Village. Journal of Human Hypertension. 1996;10(1):21–26. [PubMed: 8642186]
  71. Mirabet A. Epidemiologic Aspects of Cerebrovascular Accidents in Tunisia. Revue Neurologique (Paris) 1990;146(4):297–301. [PubMed: 2359902]
  72. Mokhobo K. P. Arterial Hypertension in Rural Societies. East African Medical Journal. 1976;52:440–44. [PubMed: 991784]
  73. Mollentze W. F., Moore A. J., Steyn A. F., Joubert G., Steyn K., Oosthuizen G. M., Weich D. J. Coronary Heart Disease Risk Factors in a Rural and Urban Orange Free State Black Population. South African Medical Journal. 1995;85(2):90–86. [PubMed: 7597541]
  74. Msamati B. C., Igbigbi P. S. Anthropometric Profile of Urban Adult Black Malawians. East African Medical Journal. 2000;77:364–68. [PubMed: 12862154]
  75. Muna W. F. The Importance of Cardiovascular Research in Africa Today. Ethnicity and Disease. 1993a;3(Suppl.):S8–12. [PubMed: 8087028]
  76. ———1993bCardiovascular Disorders in Africa World Health Statistics Quarterly 46(2):125–33. [PubMed: 8303907]
  77. Murray, C. J., and A. Lopez. 1996. The Global Burden of Disease. Washington, DC: World Bank. [PubMed: 8966556]
  78. ———1997Mortality by Cause for Eight Regions of the World: Global Burden of Disease Study Lancet 3491269–76. [PubMed: 9142060]
  79. Nan L., Tuomilehto J., Dowse G., Zimmet P., Gareeboo H., Chitson P., Korhonen H. J. Prevalence and Medical Care of Hypertension in Four Ethnic Groups in the Newly-Industrialized Nation of Mauritius. Journal of Hypertension. 1991;9(9):859–66. [PubMed: 1663988]
  80. Nethononda M. R., Essop M. R., Mbewu A. D., Galpin J. S. Coronary Artery Disease and Risk Factors in Black South Africans—A Comparative Study. Ethnicity and Disease. 2004;14(4):515–19. [PubMed: 15724770]
  81. Njelekela M., Negishi H., Nara Y., Tomohiro M., Kuga S., Noguchi T., Kanda T. et al. Cardiovascular Risk Factors in Tanzania: A Revisit. Acta Tropica. 2001;79(3):231–39. [PubMed: 11412807]
  82. Nkoua J. L., Tsombou B., Bouramoue C. Non Rheumatic Pericarditis with Effusion: Causes, Outcome and Relation to HIV-Infection. Annals of Oncology. 1999;25(97):3–6.
  83. Ogunnowo P. O., Odesanmi W. O., Andy J. J. Coronary Artery Pathology of 111 Consecutive Nigerians. Transactions of the Royal Society of Tropical Medicine and Hygiene. 1986;80(6):923–26. [PubMed: 3603641]
  84. Ohwovoriole A. E., Kuti J. A., Kabiawu S. I. Casual Blood Glucose Levels and Prevalence of Undiscovered Diabetes Mellitus in Lagos Metropolis Nigerians. Diabetes Research and Clinical Practice. 1988;4(2):153–58. [PubMed: 3342734]
  85. Okesina A. B., Oparinde D. P., Akindoyin K. A., Erasmus R. T. Prevalence of Some Risk Factors of Coronary Heart Disease in a Rural Nigerian Population. East African Medical Journal. 1999;76:212–16. [PubMed: 10442103]
  86. Omar M. A., Seedat M. A., Motala A. A., Dyer R. B., Becker P. The Prevalence of Diabetes Mellitus and Impaired Glucose Tolerance in a Group of Urban South African Blacks. South African Medical Journal. 1993;83(9):641–43. [PubMed: 8310354]
  87. Omotoso A., Kane A. Intraventricular Conduction Block in Adult Nigerians with Hypertensive Heart Disease; Epidemiological Study of Cardiovascular Disease and Risk Factors in Senegal: Cardiology—Out of Africa. Cardiovascular Journal of Southern Africa. 2000;11(3):173–74.
  88. Omran A. R. The Epidemiological Transition: A Theory of the Epidemiology of Population Change. Millbank Memorial Fund Quarterly. 1971;49:509–38. [PubMed: 5155251]
  89. ———1983The Epidemiologic Transition Theory. A Preliminary Update Journal of Tropical Pediatrics 29(6):305–16. [PubMed: 6672237]
  90. Opie L., Steyn K. Rationale for the Hypertension Guidelines for Primary Care in South Africa. South African Medical Journal. 1995;85(12):1325–28. [PubMed: 8600605]
  91. Osuntokun B. O., Adeuja A. O., Schoenberg B. S., Bademosi O., Nottidge V. A., Olumide A. O., Ige O., Yaria F., Bolis C. L. Neurological Disorders in Nigerian Africans: A Community-Based Study. Acta Neurologica Scandinavica. 1987;75(1):13–21. [PubMed: 3033973]
  92. Owoaje E. E., Rotimi C. N., Kaufman J. S., Tracy J., Cooper R. S. Prevalence of Adult Diabetes in Ibadan, Nigeria. East African Medical Journal. 1997;74:299–302. [PubMed: 9337007]
  93. Oyoo G. O., Ogola E. N. Clinical and Socio Demographic Aspects of Congestive Heart Failure Patients at Kenyatta National Hospital, Nairobi. East African Medical Journal. 1999;76:23–27. [PubMed: 10442143]
  94. Peters V. J. Developing In-House Audiovisual Programs For Use In Diabetes Education. Diabetes Education. 1983;9(2):11–18. [PubMed: 6192978]
  95. Politzer W. M., Sachs S. B. Incidence of Diabetes Mellitus in the Peri-Urban Bantu: Antenatal Surveys. South African Medical Journal. 1967;41(14):359–60. [PubMed: 6024387]
  96. Poulter, N. R. 1988. "Longitudinal Study of BP among Rural/Urban Immigrants in Kenya." In Ethnic Factors in Health and Disease, ed. D. K. Cruikshank and D. G. Beevers. Bristol: IOP Publishing.
  97. Poulter N. R., Khaw K. T., Hopwood B. E. C., Mugambi M., Peart W. S., Rose G., Sever P. S. Blood Pressure and Associated Factors in a Rural Kenyan Community. Hypertension. 1984;6:810–13. [PubMed: 6335133]
  98. Pretoria Department of Health, Medical Research Council, and Measure DHS+. 2002. South African Demographic and Health Survey 1998. Full Report. Pretoria: Department of Health. http://www​.doh.gov.za/facts/1998/sadhs98.
  99. Ranjith N., Pegoraro R. J., Rom L., Lanning P. A., Naidoo D. P. Renin-Angiotensin System and Associated Gene Polymorphisms in Myocardial Infarction in Young South African Indians. Cardiovascular Journal of South Africa. 2004;15:22–26. [PubMed: 14997233]
  100. Razum O. Monitoring Cardiovascular Disease in Zimbabwe: A Review of Needs and Options. Central African Journal of Medicine. 1996;42:120–24. [PubMed: 8791870]
  101. Reddy K. S., Yusuf S. Emerging Epidemic of Cardiovascular Disease in Developing Countries. Circulation. 1998;97:596–601. [PubMed: 9494031]
  102. Reddy, P. 1997. "Selling Deception and Disease: Tobacco Control." Paper presented at the Fourth International Conference on Preventive Cardiology, Montreal, June–July 1997. Abstract. Canadian Journal of Cardiology.
  103. ———. 2004. "Chronic Diseases." In South African Health Review 2003/04, 175–90. Durban: Health Systems Trust.
  104. Rosman K. D. The Epidemiology of Stroke in an Urban Black Population. Stroke. 1986;17(4):667–69. [PubMed: 3738949]
  105. Sarti C., Rastenyte D., Cepaitis Z., Tuomilehto J. International Trends in Mortality from Stroke, 1968 to 1994. Stroke. 2000;31(7):1588–601. [PubMed: 10884459]
  106. Seedat Y. K. The Prevalence of Hypertension and the Status of Cardiovascular Health in South Africa. Ethnicity and Disease. 1998;8(3):394–97. [PubMed: 9926910]
  107. ———. 2000. Hypertension in Developing Nations in Sub-Saharan Africa. Journal of Human Hypertension 14 (10–11): 739–47. [PubMed: 11095164]
  108. Seedat Y. K., Seedat M. A., Hackland D. B. Prevalence of Hypertension in the Urban and Rural Zulu. Journal of Epidemiology and Community Health. 1982;36:256–61. [PMC free article: PMC1052229] [PubMed: 7166680]
  109. Sen K., Bonita R. Global Health Status: Two Steps Forward, One Step Back. Lancet. 2000;356:577–82. [PubMed: 10950247]
  110. Sever P. S., Gordon D., Peart W. S., Beighton P. Blood Pressure and Its Correlates in Urban and Tribal Africa. Lancet. 1980;2(8185):60–64. [PubMed: 6105245]
  111. Shaper, A. G. 1974. "Communities without Hypertension." In Cardiovascular Disease in the Tropics, ed. A. G. Shaper, M. S. R. Hutt, and Z. Fejfar, 77–83. London: British Medical Association.
  112. Sliwa K., Damasceno A., Mayosi B. M. Epidemiology and Etiology of Cardiomyopathy in Africa. Circulation. 2005;112:3577–83. [PubMed: 16330699]
  113. Sobngwi E., Mbanya J. C., Unwin N. C., Kengne A. P., Fezeu L., Minkoulou E. M., Aspray T. J., Alberti K. G. Physical Activity and Its Relationship with Obesity, Hypertension and Diabetes in Urban and Rural Cameroon. International Journal of Obesity Related Metabolic Disorders. 2002;26(7):1009–16. [PubMed: 12080456]
  114. Statistics South Africa. 2001. Recorded Deaths, 1996. Report 03-09-01 (1996). Pretoria: Statistics South Africa.
  115. Steenkamp J. H., Simson I. W., Theron W. Cardiovascular Causes of Death at Tshepong Hospital in 1 year, 1989–1990. A Necropsy Study. South African Medical Journal. 1992;81(3):142–46. [PubMed: 1734552]
  116. Steinberg W. J., Balfe D. L., Kustner H. G. Decline in the Ischaemic Heart Disease Mortality Rates of South Africans, 1968–1985. South African Medical Journal. 1988;74(11):547–50. [PubMed: 3194802]
  117. Steyn, K. 1998. South Africa Demographic and Health Survey 1998. Pretoria: National Department of Health, chaps. 11–13.
  118. Steyn, K., and J. Fourie, eds. 1991. BRISK Study Methodology: Coronary Heart Disease Risk Factor Study in the African Population of the Cape Peninsula. MRC Technical Report 1. Cape Town: South African Medical Research Council.
  119. Steyn K., Fourie J., Lombard C., Katzenellenbogen J., Bourne L., Jooste P. Hypertension in the Black Community of the Cape Peninsula, South Africa. East African Medical Journal. 1996;73:758–63. [PubMed: 8997869]
  120. Steyn K., Rossouw J. E., Jooste P. L., Chalton D. O., Jordaan E. R., Jordaan P. C. J., Steyn M., Swanepoel A. S. P. The Intervention Effects of a Community-Based Hypertension Control Programme in Two Rural South African Towns: The CORIS Study. South African Medical Journal. 1993;83(12):885–91. [PubMed: 8115913]
  121. Swai A. B., McLarty D. G., Kitange H. M., Kikima P. M., Tatalla S., Keen N., Chuwa L. M., Alberti K. G. Low Prevalence of Risk Factors for Coronary Heart Disease in Rural Tanzania. International Journal of Epidemiology. 1993;22(4):651–59. [PubMed: 8225739]
  122. Teuscher T., Baillod P., Rosman J. B., Teuscher A. Absence of Diabetes in a Rural West African Population with a High Carbohydrate/Cassava Diet. Lancet. 1987;1(8536):765–68. [PubMed: 2882181]
  123. Thiam M., Cloatre G., Fall F., Theobald X., Perret J. L. Ischaemic Cardiopathy in Africa: Experience at the Hôpital Principal in Dakar. Médecine d'Afrique Noire. 2000;47(6):281–84.
  124. van der Sande M. A., Ceesay S. M., Milligan P. J., Nyan O. A., Banya W. A., Prentice A., McAdam K. P., Walraven G. E. Obesity and Undernutrition and Cardiovascular Risk Factors in Rural and Urban Gambian Communities. American Journal of Public Health. 2001;91(10):1641–44. [PMC free article: PMC1446846] [PubMed: 11574327]
  125. Vaughan J. P. A Brief Review of Cardiovascular Disease in Africa. Transactions of the Royal Society of Tropical Medicine and Hygiene. 1977;71:226–31. [PubMed: 329489]
  126. Vorster H. H. The Emergence of Cardiovascular Disease during Urbanisation of Africans. Public Health and Nutrition. 2002;5(1A):239–43. [PubMed: 12027290]
  127. Walker A. R., Sareli P. Coronary Heart Disease: Outlook for Africa. Journal of the Royal Society of Medicine. 1997;90(1):23–27. [PMC free article: PMC1296111] [PubMed: 9059377]
  128. Walker R. W., McLarty D. G., Kitange H. M., Whiting D., Masuki G. G., Mtasiwa D. M., Machibya H., Unwin N., Alberti K. G. Stroke Mortality in Urban and Rural Tanzania. Adult Morbidity and Mortality Project. Lancet. 2000;355:1684–87. [PubMed: 10905244]
  129. Walker R. W., Rolfe M., Kelly P. J., George M. M., James O. F. Mortality and Recovery after Stroke in The Gambia. Stroke. 2003;34(7):1604–9. [PubMed: 12817107]
  130. WHO (World Health Organization). 1999. The World Health Report 1999—Making a Difference. Geneva: WHO.
  131. ———. 2002. The World Health Report 2002—Reducing Risks, Promoting Healthy Life. Geneva: WHO. [PubMed: 14741909]
  132. ———. 2004. The World Health Report 2004—Changing History. Geneva: WHO.
  133. Wiredu E. K., Nyame P. K. Stroke-Related Mortality at Korle Bu Teaching Hospital, Accra, Ghana. East African Medical Journal. 2001;78:180–84. [PubMed: 12002067]
  134. Yusuf S., Hawken S., Ounpuu S., Dans T., Avezum A., Lanas F., McQueen M. et al. Effect of Potentially Modifiable Risk Factors Associated with Myocardial Infarction in 52 Countries (the INTERHEART Study) Lancet. 2004;364:937–52. [PubMed: 15364185]
Copyright © 2006, The International Bank for Reconstruction and Development/The World Bank.
Bookshelf ID: NBK2294PMID: 21290655

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