Prevalence of diabetes mellitus and impaired glucose tolerance in the urban population aged 30-69 years in Ribeirão Preto (São Paulo), Brazil

Abstract

Context: Diabetes mellitus prevalence has been increasing worldwide due to factors like lifestyle changes and higher life expectancy. The Brazilian Multicenter Study performed between 1986 and 1988 evaluated the prevalence of diabetes and impaired glucose tolerance. Objective: To assess the prevalence of diabetes and impaired glucose tolerance in the urban population aged 30-69 years of the city of Ribeirão Preto, SP, Brazil. Type of Study: A two-stage, cross-sectional home survey. Setting: Ribeirão Preto, São Paulo, Brazil. Participants: A random sample of 1,473 individuals. Methods: The sample plan was drawn up using a sampling scheme of stage conglomerates according to sex, age and family head income. Subjects were first screened by fasting capillary glycemia (FCG). Those that screened positive (FCG ≥ 100 mg/dl) and every seventh consecutive person who screened negative (FCG < 100 mg/dl) was submitted to a 75 g oral glucose tolerance test. The diagnosis of diabetes and impaired glucose tolerance were based on World Health Organization criteria. Results: The overall rates of diabetes and impaired glucose tolerance were 12.1 and 7.7% respectively. Men and women had similar rates of diabetes (12.0 vs. 12.1%) and impaired glucose tolerance (7.9 vs 7.3%). Differences in the rates for whites (11.6%) and nonwhites (13.3%) for diabetes were not significant, while impaired glucose tolerance was more prevalent among whites. The prevalences of diabetes and impaired glucose tolerance ranged from 3.3% and 2.6% in the 30-39 year age group to 21.7% and 11.3% in the 60-69 year age group, respectively. Obese subjects (BMI ≥ 30 kg/m2) and those with a family history of diabetes (first-degree relatives) presented higher prevalences of diabetes (22.6% and 19.7%, respectively). Conclusions: The prevalence of diabetes in Ribeirão Preto was found to be comparable to that occuring in developed countries. With respect to the Brazilian Multicenter Study we verified an increased prevalence of diabetes but a similar prevalence of impaired glucose tolerance. These findings may reflect modifications in environmental factors and lifestyle that have been occuring in Brazilian cities like Ribeirão Preto, especially regarding increasing rates of sedentary living and obesity.