Obesity-susceptibility loci and the tails of the pediatric BMI distribution

Abstract

ObjectiveWe aimed to determine if previously identified adult obesity susceptibility loci were associated uniformly with childhood BMI across the BMI distribution.Design and MethodsChildren were recruited through the Children's Hospital of Philadelphia (n=7225). Associations between the following loci and BMI were assessed using quantile regression: FTO (rs3751812), MC4R (rs12970134), TMEM18 (rs2867125), BDNF (rs6265), TNNI3K (rs1514175), NRXN3 (rs10146997), SEC16B (rs10913469), and GNPDA2 (rs13130484). BMI z-score (age and gender adjusted) was modeled as the dependent variable, and genotype risk score (sum of risk alleles carried at the 8 loci) was modeled as the independent variable.ResultsEach additional increase in genotype risk score was associated with an increase in BMI z-score at the 5th, 15th, 25th, 50th, 75th, 85th and 95th BMI z-score percentiles by 0.04 (±0.02, p=0.08), 0.07 (±0.01, p=9.58 × 10-7), 0.07 (±0.01, p=1.10 × 10-8), 0.09 (±0.01, p=3.13 × 10-22), 0.11 (±0.01, p=1.35 × 10-25), 0.11 (±0.01, p=1.98 × 10-20), and 0.06 (±0.01, p=2.44 × 10-6), respectively. Each additional increase in genotype risk score was associated with an increase in mean BMI z-score by 0.08 (±0.01, p=4.27 × 10-20).ConclusionObesity risk alleles were more strongly associated with increases in BMI z-score at the upper tail compared to the lower tail of the distribution.