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

Many genomic risk factors are associated with obesity. There are few prospective studies in infants, where genomic factors may have a more influential role. Over 1800 families from various races or ethnicities have been recruited in prenatal stage, in the longitudinal genomic study of “First 1000 Days of Life”, at Inova Translational Medicine Institute. 650 children had clinical and genomic data available at age 12 months. Whole genome sequencing was performed on blood. Weight for length at 12 months was calculated using WHO gender specific growth charts with the following definitions: overweight ≥85th, obese ≥95th, severely obese ≥99th percentiles.  A supervised genetic analysis was conducted using the SKAT for the association of rare variants (MAF<=0.1) with obesity. Gene-set level p-values were computed for 363 obesity related genes from the human obesity gene map. Chi-square and One-way ANOVA were used to test for association of clinical and social factors with obesity. Of the 650 infants, 31% were overweight, 20% obese and 13% severely obese. After adjusting for multiple testing with Bonferroni correction, only two genes were significant at the 0.1 level, namely, WT1 (P=0.0033) and CNR1 (P=0.090), for the severely obese group. None of the genes were significant after Bonferroni correction for the overweight or obese groups. Clinical and socials factors that were significantly associated (p<0.05) with being overweight and obese in all 3 groups were Hispanic origin, lower maternal education and any juice consumption at 12 months.