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Am J Public Health. 2003 February; 93(2): 318–323.
PMCID: PMC1447737

Relation of Dietary Quality, Physical Activity, and Smoking Habits to 10-Year Changes in Health Status in Older Europeans in the SENECA Study

Annemien Haveman-Nies, PhD, Lisette C.P.G.M. de Groot, PhD, Wija A. van Staveren, PhD, and for the Seneca investigators

Abstract

Objectives. This study investigated the effect of healthy lifestyle behaviors on self-rated health and self-care ability over a 10-year follow-up period in older persons in the SENECA study.

Methods. Health status and lifestyle behaviors were examined in 1988/1989, 1993, and 1999 in 216 men and 264 women, born between 1913 and 1918, from 7 European countries.

Results. Self-rated health and self-care ability declined in men and women with healthy and unhealthy lifestyle habits over the 10-year follow-up period. Inactive and smoking persons had an increased risk for a decline in health status as compared with active and nonsmoking people. No effect of a healthy, Mediterranean-like diet on the deterioration in health status was observed.

Conclusions. Being physically active and nonsmoking delayed deterioration in health status in older participants aged 70 to 75 years in the SENECA study. (Am J Public Health. 2003;93:318–323)

A major challenge today is how to improve overall health and quality of life at older ages. In Western societies, the average life expectancy has increased substantially in the past century, resulting in a much greater proportion of people surviving to older ages.1 Increasing age is associated with comorbidity, cognitive impairments, and disability and loss of independence.2–5 If the average age at onset of ill health remained unchanged, an increased life span would mean more years of ill health before death. This is not the intended result of health promotion programs. Ideally, people should survive to an advanced age with their vigor and functional independence maintained, and morbidity and disability should be compressed into a relatively short period before death.6,7 In searching for determinants of healthy aging, we investigated whether the lifestyle factors not smoking, being physically active, and having a high-quality diet, which are related to a higher survival rate,8,9 are also related to a better health status at older ages.

Health status has many dimensions—physical, emotional, and social—and can be operationalized through assessments of these different dimensions or through subjective self-assessments of overall health. In this study, we focused on 2 indicators of health status: self-rated health and functional status (self-care). Functional status is an objective indicator of health status that specifies the degree to which a person depends on others for help in performing activities of daily living. Self-rated health is a subjective health indicator that summarizes individual health aspects, weighed by personal values and preferences.10,11 In addition to these individual differences, gender, age, and culture are related to self-rated health.12–18 Self-rated health and functional status are good predictors of mortality13,19,20 and are related to morbidity.15,21 Because multiple conditions usually occur together in older people, overall health measurements such as self-rated health and functional status are useful indicators with which to examine the effect of lifestyle factors on health status.

This study investigated the relation of baseline healthy lifestyle behaviors—being physically active, being a nonsmoker, and having a high-quality diet—to 10-year changes in self-care ability and self-rated health of participants, aged 70 to 75 years, in the Survey in Europe on Nutrition and the Elderly: a Concerted Action (SENECA) study.

METHODS

Study Population

The SENECA study was a longitudinal study involving 3 times of measurement, in 1988/1989, 1993, and 1999. At baseline, participants were selected from a random age- and sex-stratified sample of inhabitants from the following small European towns: Hamme, Belgium; Roskilde, Denmark; Padua, Italy; Culemborg, the Netherlands; Vila Franca de Xira, Portugal; Betanzos, Spain; and Yverdon, Switzerland.22 All inhabitants born between 1913 and 1918 were eligible to be enrolled in the study. The only exclusion criteria were living in a psychogeriatric nursing home, not being fluent in the country’s language, and not being able to answer questions independently.23 Participation rates varied from 37% to 62%.22 At baseline, 759 men and 778 women were enrolled in the SENECA study. About half of the male population and a quarter of the female population died during the 10-year follow-up period. From the remaining population, 69% participated in the study in 1993, and 58% participated in the study in 1999 (Figure 1 [triangle]). Complete sets of information from the 3 surveys were retrieved for 216 men and 264 women.

FIGURE 1
—Flow of participants in the SENECA study.

Health Status and Lifestyle Factors

Information on health status was collected with a general interview.23 Questions were asked about chronic diseases, self-rated health, and self-care ability. The number of chronic diseases was determined by calculating the prevalence of the following chronic diseases: ischemic heart disease, stroke, respiratory problems, malignancy, arthritis, and diabetes. Self-rated health was measured by the question “How would you judge your present health in general?” The answer categories were “very poor,” “poor,” “fair,” “good,” and “very good.” In all 3 surveys, this question was preceded by questions on chronic diseases, medication, and physical functioning. The answer categories were separated into a group with good or very good health status and a group with fair, poor, or very poor health status. Self-care ability was assessed through questions about the following activities of daily living: walking between rooms, using the toilet, washing, dressing and undressing, getting in and out of bed, and feeding. The level of competence was expressed as “no difficulty to perform an activity,” “with difficulty but without help,” “only with help,” and “not able to perform this activity.”24 Functional independence was defined as no difficulty or difficulty in performing only 1 self-care activity.

The lifestyle factors smoking and physical activity were measured with a general interview, and food intake data were collected via the modified dietary history method.22 On the basis of the finding that the overall risk of former smokers approaches that of those who never smoked after 15 to 20 years of abstinence, the following 2 smoking groups were composed: (1) current smokers and former smokers with 15 or fewer years of abstinence, indicated as smokers; 2) never smokers and former smokers with more than 15 years of abstinence, indicated as nonsmokers.25 Physical activity was measured with the Voorrips questionnaire, a questionnaire that includes a household, sports, and leisure-time component.26 To classify physical activity, sex-specific tertiles (low, intermediate, and high physical activity) were constructed from data for the total baseline population.26 Two activity groups were composed: (1) an inactive group with participants from the low-activity tertile, and (2) an active group with participants from the intermediate- and the high-activity tertiles.

Dietary quality groups were based on a modified Mediterranean Diet Score.8,27,28 The score included the following items: fat (by monounsaturated-to-saturated fat ratio); alcohol; legumes, nuts, or seeds; cereals; vegetables and fruits; meat and meat products; and dairy products. Intake values were adjusted to daily intakes of 10 500 kJ (2500 kcal) for men and 8400 kJ (2000 kcal) for women. A detailed description of the diet score is given by van Staveren et al.28 The diet score ranged from 0 (low-quality diet) to 7 (high-quality diet). Two dietary groups were composed: (1) a lowdietary-quality group with diet scores of 4 or less, and (2) a high-dietary-quality group with diet scores greater than 4.

Statistical Analyses

Statistical analyses were carried out with SAS (Version 6.12; SAS Institute Inc, Cary, NC). Baseline lifestyle factors and health status were described for the participants who participated in all 3 (1988/1989, 1993, and 1999) SENECA surveys (full participants); the participants who dropped out in the 1993 or 1999 surveys; and the persons who died during the 10-year follow-up period. Health status measures and lifestyle factors of the male and female full participants were compared with those of the deceased persons and participants who dropped out by the χ2 test for categorical variables and the Wilcoxon rank sum test for continuous variables (P ≤ .05).

Longitudinal changes in self-rated health and self-care ability for the period 1988 to 1999 were tested for the full participants with the Wilcoxon signed rank test in men and women and in the groups with healthy and unhealthy lifestyle behaviors.

To investigate the effect of lifestyle factors on the deterioration in health status, odds ratios and 90% confidence intervals were calculated (PROC LOGISTIC; SAS Institute Inc, Cary, NC) in a subsample of participants who were functionally independent at baseline and a subsample who reported their baseline health status as “good.” Odds ratios for deterioration in health status were calculated for the various physical activity, smoking, and dietary quality groups in men and women separately. In this logistic model, allowance was made for country and age at baseline. Because of the divergent low number of persons in Vila Franca de Xira who reported their health as “good,” the Portuguese participants were excluded from the calculation of odds ratios for deterioration in self-rated health (see Discussion).

RESULTS

Table 1 [triangle] describes the baseline characteristics of participants who completed the study, those who dropped out, and those who died during the study. At baseline, full participants had a better health status and more favorable health behaviors than did deceased participants. Minor differences between participants who dropped out and full participants were found. In general, men had better health status than women in all 3 participant categories.

TABLE 1
—Baseline Health and Lifestyle Characteristics of Full Participants,a Participants Who Dropped Out,b and Deceased Participantsc: the SENECA Study

Table 2 [triangle] presents the results of 2 indicators of health status during the 3 surveys. Self-rated health and self-care ability decreased significantly over the 10-year follow-up period in both male and female participants. The greatest deterioration in health status was observed over the period 1993 to 1999. Health status declined (significantly) over the period 1988 to 1999 in men and women with healthy as well as unhealthy lifestyle factors, except for self-rated health in female smokers (n = 19). However, active men and women kept their positive health ratings and level of independence than did inactive persons. In addition, nonsmoking men remained in better health than male smokers. An effect of a high-quality diet on self-ratings of health and self-care ability was not observed for men and women.

TABLE 2
—Health Status Measures for Full Participants With Healthy and Unhealthy Lifestyle Behaviors, by Sex and Survey: the SENECA Study

Most of the men and women had the same health ratings (70%) and self-care ability (83%) at the beginning and the end of the 10-year follow-up period. Only a quarter of this stable group already had negative selfratings of health at baseline, and very few persons (3%) were already functionally dependent at that point. Participants with a good baseline health status were selected in order to investigate the effect of lifestyle on deterioration in health status. Lifestyle habits of the persons with a decline in health status over the period 1988 to 1999 were compared with the habits of the persons who maintained a good health status (Table 3 [triangle]). Inactive and smoking men had a 2 to 3 times increased risk of experiencing a decline in self-rated health or of becoming dependent compared with men with an active or a nonsmoking lifestyle. For women, no effect of inactivity on decline in self-rated health was observed, but inactivity increased the risk of dependence. No association between diet and risk of deterioration in health status was observed for men or women.

TABLE 3
—Risk of Deterioration in Health Status (Odds Ratios [ORs] and 90% Confidence Intervals [CIs]a) Resulting From an Unhealthy Lifestyle in Elderly European Men and Women With Good Health at Baseline: the SENECA Study

DISCUSSION

Overall, self-rated health and self-care ability declined in men and women with healthy and unhealthy lifestyle habits. Men with a healthy lifestyle, including those who were nonsmoking and physically active, remained in better health and had a delay in the onset of functional dependence, compared with men with unhealthy behaviors. In women, only an active lifestyle was positively related to functional independence in this older population.

Measures of Lifestyle Factors and Health Status

The strength of this European study was the inclusion of a large diversity of food and lifestyle factors studied with validated measures.23,26 In an earlier study within the SENECA population, we found that dietary patterns of differing quality could be measured with diet scores.38 In the SENECA study, dietary intake, lifestyle factors, and indicators of health status were collected according to a strictly standardized methodology both over time and across Europe. In the SENECA operations manual,23 sample drawings, instructions for interviewers, and coding procedures were provided, and questionnaires were printed. Researchers from all centers participated in training sessions to standardize the data collection procedures. Although these standardized procedures were followed, the measurement of health status indicators in SENECA and in older populations in general needs some extra attention. Therefore, this measurement is discussed more extensively in this section.

In this study, an overall health indicator and a health indicator that focused on functional independence were used because each was considered to result from various underlying diseases and conditions. Both self-rated health and self-care ability are good predictors of mortality13,20 and are related to morbidity.15,21 In the SENECA study, most of the population had 1 or more chronic diseases, but only a small percentage was functionally dependent or reported “fair” or “poor” overall health. In line with this finding, the literature shows that the effect of diseases on perceived disease burden is not straightforward. The type of disease or impairment21,30,31 and also other factors, such as positive mood and social support, affect people’s perception of health.17 Because of the multidimensionality of health status, we used 2 complementary indicators of health status to measure different manifestations of health.

In contrast to participants from the other European centers, most participants from Vila Franca de Xira reported “poor” overall health. In this town, the number of chronic diseases (self-reported) and cases of depression was high compared with other European centers,32,33 but the mortality rate over the 10-year follow-up period was not correspondingly high.34 Lifestyle habits of Portuguese participants were comparable to the habits of other southern Europeans. It seems that Portuguese participants possessed the worst health, but their poor health status did not involve an increased mortality risk. A higher prevalence of nonfatal diseases and a tendency to overreport health problems could explain these negative self-assessments of health. Self-rated health was not related to both morbidity and mortality, so that the Portuguese self-ratings deviated from those of the participants in other European centers. Therefore, we decided to exclude the participants of Vila Franca de Xira from the pooled analyses of lifestyle factors with self-rated health.

Overall, self-rated health and self-care ability deteriorated for men and women over the period 1988 to 1999. The pattern of decline differed among the health indicators. The loss of independence was rather consistent throughout the individual centers, whereas for self-rated health, the pattern was more dispersed, and an improvement in self-rated health was even observed in some centers. Although both indicators are inclusive measures, they focus on different aspects of health. Hoeymans et al.12 reported that the association between functional status and self-rated health weakens with increasing age. This trend could be explained by the finding that older respondents are more likely than their younger counterparts to base their health appraisals on attitude or behavior rather than on conditions, symptoms, or functioning.35 More than self-care ability, self-rated health refers to changes in quality of life or well-being, and together these health indicators reflect different aspects of changes in health status with aging.

Longitudinal Studies

Selectivity of the research population can be introduced at different stages of the study. In the SENECA study, a tendency for healthier persons to participate in the baseline study was observed.22 In addition, an important limitation of longitudinal studies of older populations is dropout due to mortality, diseases, or other reasons.36 In the SENECA study, a high proportion of the participants dropped out of the study for various reasons. Table 1 [triangle] shows that the full participants had better health status and health behaviors than did those who died over the 10-year follow-up period. The high proportion of dropout due to mortality is inevitable in longitudinal studies of older populations. The full participants did not have better health status than the dropout group. With regard to lifestyle habits, participants who dropped out had a lower dietary quality than did full participants. Possibly, those who dropped out were less interested in diet and grew tired of reporting their dietary intake. The dropout for reasons other than mortality does not impair the generalization of the results to the survivor population.

Lifestyle Factors

During the past 3 decades, southern European countries experienced higher gains in life expectancy than did northern European countries, mainly because of much lower heart disease death rates.37 Migration studies show that these differences are likely to be a result of environmental rather than genetic factors. These results indicate that a proportion of the diseases associated with aging can be prevented or at least postponed.2 The European SENECA study included great variation in cultural and environmental factors influencing dietary patterns and lifestyle habits.38 As in other studies, these lifestyle factors appeared to be strong predictors of overall mortality8,9,27,29,39; therefore, the SENECA study included valid measures of lifestyle factors to relate to health status.

Relation Between Lifestyle Factors and Health Status

The relation between lifestyle and health status was investigated for the 3 modifiable factors—physical activity, smoking, and dietary quality—in a group of older survivors of a 10-year follow-up period. In our study, physical activity and nonsmoking were related to better functioning and overall health status compared with inactivity and smoking. In a subsample of participants with a good baseline health status, these healthy lifestyle behaviors delayed deterioration in health status. In some cross-sectional and longitudinal studies, physical activity and nonsmoking delayed the deterioration in health status or were related to a better health status compared with unhealthy behaviors.40–43 The relation between these 2 lifestyle factors and indicators of health status was more pronounced for men than for women. In women, only physical activity was related to a delay in onset of functional dependence. The low number of smokers, but also a different process by which women incorporate information into their self-ratings of health, seems to be responsible for this. The finding that self-rated health is less strongly related to mortality in women than in men affirms this and indicates that women are more likely to take subjective health aspects into account, whereas men are more likely to consider physical functioning.13,44

In our study, having a high-quality, Mediterranean-like diet did not delay the deterioration in health status, compared with having a low-quality diet. This is the first study that related dietary pattern to the inclusive measures functional status and self-rated health.40 Studies of chronic diseases have shown that dietary patterns can predict coronary heart disease and cancer.2,39,45 Although these studies found associations between dietary patterns and diseases, no association with health status was found in our study. Because we found a relation among physical activity, nonsmoking, and health status in our study, it is likely that the complexity of the dietary pattern and the complicated relation between diseases and perceived disease burden attenuated the association between dietary quality and health status.

To conclude, in this study 2 inclusive indicators of health status measured different manifestations of health status in a group of healthier and more health-concerned older persons. As functional independence and “good” self-rated health declined, different patterns emerged for healthy and unhealthy lifestyle behaviors. The healthy lifestyle behaviors physical activity and not smoking, which were related to survival, also were related to a delay in deterioration in health status. Sex differences emerged for the relation between lifestyle factors and indicators of health status.

Acknowledgments

Human Participant Protection
This study was approved by the institutional review board of Wageningen University in 1999.

Notes

A. Haveman-Nies conducted the statistical analysis and wrote the main body of the article. L. C. P. G. M. de Groot and W. A. van Staveren were responsible for data collection of the SENECA study. They contributed to the methodology of this study and the interpretation of the results.

Peer Reviewed

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