Obesity-Related Genetic Variants and their Associations with Physical Activity.

Background: Meta-analysis of genome-wide association studies identified obesity-related genetic variants. Due to the pleiotropic effects of related phenotypes, we tested six of these obesity-related genetic variants for their association with physical activity: fat mass and obesity-associated ()(rs9939609)T>A, potassium channel tetramerization domain containing () (rs11084753)G>A, melanocortin receptor4 ()(rs17782313)T>C, neuronal growth regulator 1 ()(rs2815752)A>G, SH2B adapter protein 1 ()(rs7498665)A>G, and transmembrane protein18 ()(rs6548238)C>T.

Method: European-American women ( = 263) and men ( = 229) (23.5 ± 0.3 years, 24.6 ± 0.2 kg/m) were genotyped and completed the Paffenbarger physical activity Questionnaire. Physical activity volume in metabolic energy equivalents [MET]-hour/week was derived from the summed time spent (hour/week) times the given MET value for vigorous, moderate, and light intensity physical activity, and sitting and sleeping, respectively. Multivariable adjusted [(age, sex, and body mass index (BMI)] linear regression tested associations among genotype (dominant/recessive model) and the log of physical activity volume.

Result: (rs17782313)T>C explained 1.1 % ( = 0.02), (rs6548238)C>T 1.2 % ( = 0.01), and (rs7498665)A>G 0.6 % ( = 0.08) of the variability in physical activity volume. Subjects with the C allele spent 3.5 % less MET-hour/week than those with the TT genotype ( = 0.02). Subjects with the T allele spent 4.1 % less MET-hour/week than those with the CC genotype ( = 0.01). Finally, subjects with the GG genotype spent 3.6 % less MET-hour/week than A allele carriers ( = 0.08).

Conclusion: Our findings suggest a shared genetic influence among some obesity-related gene loci and physical activity phenotypes that should be explored further. Physical activity volume differences by genotype have public health importance equating to 11-13 lb weight difference annually.