Outside Brazil the prevalence of type 2 diabetes mellitus (DM) is higher in blacks than in whites. Women from the obesity outpatient clinic of Professor Edgard Santos University Hospital, Salvador - BA, were studied, to assess whether dark skin color have higher prevalence of type 2 DM and impaired glucose tolerance (IGT), diagnosis based on the World Health Organization criteria, independently of age and body mass index (BMI). Skin color was classified as light (n= 166), medium (n= 186) and dark (n= 128). Plasma glucose level was determined by the glucose oxidase method. Oral glucose tolerance test was performed in all patients, except for 14 that were known to have DM. Patients with light, medium and dark skin color were similar regarding age, BMI and waist/hip ratio. The prevalence of DM, however, was significantly higher (p< 0.05) in women with dark (13.3%) as compared with light skin (7.2%). The prevalence of IGT was also higher, although statistically not significant (p= 0.088), in patients with dark (18.8%) than with light (12.7%) skin. The odds of receiving the diagnosis DM or IGT was 1.9 times higher in women with dark than with light skin [odds ratio (OR)= 1.9, 95% confidence interval (CI)= 1.1-3.2, p< 0.05]. This association was not importantly altered (OR= 1.7, 95% CI= 1.0-2.9) and remained marginally significant (p= 0.069), even after the logistic regression adjustment for age and BMI. In this study, obese women with dark skin color had higher association with DM and IGT, independently of age and BMI.
Type 2 diabetes; Impaired glucose tolerance; Obesity; Skin color; Race
