Clinical, Social, and Genetic Factors Associated with Obesity at 12 Months of Age

Objective: To examine genomic, social, and clinical risk factors of ≥85 weight for length percentile (WFLP) at 12 months.

Study Design: Children in this study had whole-genome sequencing, and clinical and social data were collected. WFLPs at 12 months of age were grouped as follows: (1) <85th, (2) ≥85th to <95th, (3) ≥95th to <99th, and (4) ≥99th. Whole-genome sequencing data were used to analyze rare and common variants, and association of clinical and social factors was examined.

Results: A total of 690 children were included; WFLPs were 422 (61.2%) <85th, 112 (16.2%) ≥85th-<95th, 89 (12.9%) ≥95th-<99th, and 67 (9.7%) ≥99th. Family-related risk factors associated with greater WFLP were greater paternal body mass index, WFLP ≥99th OR 1.10 (1.03-1.16), and greater than recommended weight gain in pregnancy, WFLP ≥85th-<95th OR 1.90 (1.09-3.26). More breast milk at 6 months was protective factor: WFLP ≥85th-<95th, OR 0.98 (0.97-0.99), WFLP ≥95th-<99th OR 0.98 (0.97-0.99), and WFLP ≥99th OR 0.98 (0.96-0.99). Although none of the variants reached genome-wide significance, there was a trend toward increased prevalence of genetic variants within or near genes previously associated with obesity in children with WFLP ≥99th.

Conclusion: This cross-sectional study identified several modifiable factors, including increased weight gain in pregnancy and decreased breast milk at 6 months, associated with greater WFLP at 12 months. Strong genetic factors were not identified.