High Incidence of Diabetes Mellitus Among a Middle-Aged Population in Iran: A Longitudinal Study

Objectives: There are few data concerning the incidence rates of diabetes in Iran. This study aimed to determine the incidence of diabetes and its risk factors in a middle-aged population in Iran.

Methods: All of the people who participated in the first phase of the Shahroud eye cohort study were invited to the study in 2014; after signing informed consent forms, a total of 4737 people 45 to 69 years of age were enrolled in the second phase of the study (participation rate: 91.3%). The 5-year incidence rate of diabetes was determined by age and sex, and we used the binomial logistic regression model to calculate the risk ratio.

Results: The prevalence of diabetes in the second phase was 20.19% in men, 26.45% in women and 23.89% in the total group. The 5-year incidence of diabetes was 11.19% in men, 15.55% in women and 13.73% in both sexes. With increases in age, the incidence of diabetes rose in both sexes. Age (risk ratio [RR]: 1.02; CI 95%: 1.01 to 1.03) hypertension (RR: 1.41; CI 95%: 1.15 to 1.74), being overweight (RR: 2.17; CI 95%: 1.64 to 2.88) and obesity (RR: 3.4; CI 95%: 2.53 to 4.41) were associated with increased risks for the incidence of diabetes.

Conclusions: This study is 1 of the few studies in Iran that has reported the incidence of diabetes. Because the incidence of diabetes was high in the studied population, it is necessary for the health system to design and implement emergency intervention to prevent further spread of diabetes and its complications.