Prevalence of high HbA1c levels in Brazilian adolescents: The Study of Cardiovascular Risk in Adolescents.

AIM: To evaluate the prevalence of elevated glycated haemoglobin (HbA1c) levels in a population of adolescents participating in the Study of Cardiovascular Risk in Adolescents.

METHODS: This is a school-based cross-sectional study based on a complex sample of adolescents 12-17years old representative at the national and macro-regional levels and for each Brazilian state capital. Blood was collected in schools and then evaluated in a single laboratory. HbA1c levels were considered elevated if ⩾5.7% (39mmol/mol) and were analyzed according to sex, age, macro-region, type of school, skin color, and nutritional status.

RESULTS: Data from 37,804 adolescents were analyzed. The mean level of HbA1c was 5.4% (95%CI 5.4-5.4) (36mmol/mol [95%CI 36-36]), and 20.5% (95%CI 19.1-22.0) of adolescents presented values ⩾5.7% (⩾39mmol/mol). Among males, 23.6% (95%CI 21.8-25.6) showed elevated HbA1c levels compared to 17.5% (95%CI 15.9-19.2) observed in females. The prevalence of elevated levels of HbA1c was higher in adolescents with black skin color (27.6%; 95%CI 23.2-32.4) vs. white skin color (16.9%; 95%CI 15.4-18.5), and higher in those who studied in public schools (21.6%; 95%CI 20.0-23.4) vs. private schools (16.7%; 95%CI 14.7-19.0). Among obese adolescents, 29.7% (95%CI 25.4-34.3) had elevated levels of HbA1c, compared to 19.3% (95%CI 18.0-20.7) in normal weight students and 19.7% (95%CI 17.1-22.6) in overweight adolescents.

CONCLUSIONS: Obese male adolescents of lower socioeconomic status had a higher prevalence of elevated HbA1c levels. Our findings highlight the importance of focusing on this high risk group for interventions to prevent diabetes.