Association of Ancestral Genetic Admixture and Excess Weight at Twelve Months of Age

Background/Objective: Understanding the influence of genetically determined ancestry may give insight into the disparities of obesity seen in different ethnic groups beginning at a very early age. Aim: To investigate the relationship between children's ancestral genetic proportions and excess weight at 12 months of age. Methods: Eight hundred twenty-one 12-month-old children were included in this cross-sectional study. Their genetic admixture was estimated using the ancestry and kinship tool kit by projecting the samples into the 1000 Genomes principal component database. Weight-for-length percentile (WFLP) at 12 months of age was categorized as <95th percentile or >= 95th percentile. Multiple logistic regression analysis was performed to calculate odds ratios (ORs) with 95% confidence intervals (CIs) for the association of admixture proportions, including European (EUR), admixed American (AMR), African (AFR), South Asian (SAS), and East Asian (EAS) populations, with WFLP categories, adjusting for maternal education, birth weight, frequency of breastfeeding, and juice consumption. Results: Eight hundred twenty-one children were included; WFLP <95th percentile = 671 (81.7%) and WFLP >= 95th percentile = 150 (18.3%). Crude ORs showed that the EUR admixture was protective [OR 0.45 (95% CI 0.27-0.74)], whereas AMR [OR 3.85 (95% CI 1.92-7.70)] and AFR [OR 5.70 (95% CI 2.19-14.85)] admixtures were positively associated with excess weight. After adjusting for confounding variables, only the AFR admixture was associated with WFLP >= 95th percentile [OR 7.38 (95% CI 2.31-23.59)]. Conclusions: AFRs remain associated with early excess weight after accounting for confounding variables, suggesting that this ancestral genetic background may contribute to the differences seen in early childhood obesity.