The prevalence of diabetes in Rio de Janeiro, Brazil. The Cooperative Group for the Study of Diabetes Prevalence in Rio De Janeiro.

OBJECTIVE

To assess the prevalence of diabetes and impaired glucose tolerance (IGT) in the adult population of Rio de Janeiro, a two-stage cross-sectional survey was carried out in a random sample of 2,051 individuals aged 30-69 years from Rio de Janeiro city in Brazil.

RESEARCH DESIGN AND METHODS

Subjects were first screened by fasting capillary glycemia (FCG). All individuals who screened positive (FCG > 5.6 mmol/l) and every sixth consecutive person who screened negative (FCG < 5.6 mmol/l) were subjected to a 75-g glucose load. Diagnoses of diabetes and IGT were based on World Health Organization criteria.

RESULTS

Results from every sixth individual who screened negative were extrapolated to all individuals who screened negative after adjustment for some potential bias in the subsample. Age-adjusted prevalence rates for diabetes and IGT were 7.1 and 9.0%, respectively. The rates were higher (P < 0.01) among women than among men (8.7 vs. 5.2% for diabetes and 11.7 vs. 5.8% for IGT), among obese individuals than among nonobese individuals (7.9 vs. 6.2% for diabetes and 11.4 vs. 7.3% for IGT), and among those with family history of diabetes than among those without family history of diabetes (12.4 vs. 4.8% for diabetes and 13.8 vs. 6.7% for IGT). The rates for diabetes and IGT increased with age, being 1.7 and 4.5%, respectively, for the age-group of 30-39 years, 3.9 and 8.5% for the age-group of 40-49 years, 13.6 and 13% for the age-group of 50-59 years, and 17.3 and 15.3% for the age-group of 60-69 years (P < 0.01). The prevalence of diabetes was higher among individuals with low educational levels than among those with high educational levels (7.3 vs 4.2%). For IGT, the rates increased from the group with intermediate level of education (8.3%) to the low- (11.3%) and high-education group (12.6%). Differences in the rates for whites and non-whites (6.9 vs. 7.1% for diabetes and 8.8 vs. 9.6% for IGT) were not statistically significant. Among those with confirmed diabetes in the survey, 27.6% did not know of their diabetic condition. Among previously diagnosed diabetes (self-reported diabetes), 19.5% were not being treated, 31.8% were on diet only, 40.7% were on oral hypoglycemic drugs, and 8.0% were on insulin. Self-reported prevalence of diabetes was 0.1% for the population < 30 years of age, 4.3% for the 30-69 year old age-group, and 16.6% for those > 70 years of age.

CONCLUSIONS

The numbers found for Rio de Janeiro are similar to those for more developed countries and lead us to conclude that the impact of diabetes on public health is the same as in those countries where this disease is considered an important health problem.