Racial differences in HbA1c: a cross-sectional analysis of a Brazilian public primary care population.

ABSTRACT

BACKGROUND: Blacks show higher levels of HbA1c in studies with different populations and are disproportionately affected by most diabetes-related complications. AIMS: The study aims to investigate if the prevalence of altered glycated hemoglobin (HbA1c) varies with skin color and if there is a familial aggregation of either skin color and HbA1c. METHODS: The study used the CAMELIA study (Cardio-Metabolic-Renal familiar) population, conducted between June 2006 and December 2007 (cross sectional). Families were recruited from 13 Family Doctor Program Unities of Niteroi, Brazil, a highly miscegenated population. The visits included questionnaire, medical consultation, anthropometric and nutritional assessment. Blood pressure, blood/urine samples were collected. The dosage of HbA1c was performed by immunoturbidimetry in Labmax 240 equipment. RESULTS: We compare data of 241 (25.5%) Blacks, versus 422 (44.7%) Mulattos or 272 (28.8%) Whites. The groups did not differ significantly with regard to most measures. Blacks had the lowest levels of income/education, higher frequency of diabetes and hypertension (p<0.20) as higher levels of HbA1c (p<0.05) that persisted after adjusting for possible confounders. Among blacks, the correlations between siblings of HbA1c were higher than among white/mulatto, reaching 86% versus 50%, respectively. CONCLUSION: Those results indicate that Brazilian Blacks patients must have more attention, focusing on diabetes preventive care. Longitudinal studies are needed to address the question if the altered level of HbA1c has a real clinical impact.