Background: Studies in admixed populations show that the prevalence
of obesity and related diseases, such as type 2 diabetes and hypertension,
may vary by ethnic group. The aim of this study was to
investigate the relationship of genetic ancestry with phenotypes associated
with obesity in a sample of school children and adolescents
from Ouro Preto, Minas Gerais.
Methods: We used data from genetic ancestry of 189 individuals
previously determined by 15 ancestry informative markers (AIMs),
and segregated individuals into three ancestral groups (predominantly
African (PAFR), predominantly mixed (PMIX), and predominantly
European (PEUR)) using the proportion of ancestry. The ancestral
groups were compared with mean values of anthropometric, clinical,
biochemical, and demographic variables. The simple linear regression
analysis was used to test whether differences in mean values of
the dependent variables (blood pressure and glucose) between the ancestral
groups were dependent on the other variables.
Results: Our results show that the proportions of African (F = 144.2,
P < 0.001), Amerindian (F = 15.5, P < 0.001) and European (F =
184.9, P < 0.001) ancestry differed significantly (P < 0.001) among
the three ancestral groups. PAFR individuals had higher mean blood
pressure (P ≤ 0.029) and glucose (P = 0.025) as compared to PEUR.
In the linear regression model, the difference in systolic blood pressure
(SBP) values remained significant in all models tested and independent
of confounding variables (P ≤ 0.041). The difference in
diastolic blood pressure values observed in PAFR and PEUR groups
did not remain significant when the metabolic profile was included
in the tested model (P = 0.097). The difference in glucose values was
significant only between PMIX and PEUR groups and independent of
the settings (P ≤ 0.037).
Conclusion: The positive correlation between genetic ancestry and
SBP and glucose in Brazilian children and adolescents suggests the
need for special care in the subgroups of this population
