Genomic ancestry and glycemic control in adolescents with type 1 diabetes: A multicenter study in Brazil

To determine the influence of genomic ancestry (GA) and self-reportedcolor-race (SRCR) on glycemic control in adolescents with type 1 diabetes (T1D) in an admixed population.

This multicenter nationwide study was conducted in 14 public clinics in 10 Brazilian cities. We estimated global and individual African, European, and Native Amerindian GA proportions using a panel of 46 AIM-INDEL markers. From 1760 patients, 367 were adolescents (20.9%): 184 female (50.1%), aged 16.4 ± 1.9 years, age at diagnosis 8.9 ± 4.3 years, duration of diabetes 8.1 ± 4.3 years, years of study 10.9 ± 2.5 and HbA1c of 9.6 ± 2.4%.

Patients SRCR as White: 176 (48.0%), Brown: 159 (43.3%), Black: 19(5.2%), Asians: 5 (1.4%) and Amerindians: 8 (2.2%). The percentage of European GA prevailed in all groups: White (71.1), Brown (58.8), Black (49.6), Amerindians (46.1), and Asians (60.5). Univariate correlation was noted between A1c and African GA, r = 0.11, P = .03; years of study, r = -0.12 P = .010, and having both private and public health care insurance (r = -0.20, P < .001). After adjustments, the multivariate logistic analysis showed that SRCR or GA did not influence glycemic control.

A high percentage of European GA was noted in our patients, even in those who self-reported as non-White, confirming the highly admixed ethnicity of the Brazilian population. Better glycemic control was associated with having both types of health care; however, there was no association between glycemic control with GA or SRCR. Future prospective studies with other admixed populations are necessary to confirm our findings.