Genetic variants in vitamin D metabolism-related genes and body mass index: analysis of genome-wide scan data of approximately 7000 Chinese women

Vitamin D deficiency has been consistently associated with obesity. However, it is unclear whether vitamin D deficiency is the cause or consequence of obesity. We investigated this question by evaluating the association between genetic variants in vitamin D metabolism pathway genes and obesity-related traits. Using directly genotyped and imputed data from a genome-wide association study of 6922 women aged 25–70 years, we examined the association of 198 single-nucleotide polymorphisms (SNPs) in vitamin D pathway genes ( CYP27A1, CYP27B1, CYP24A1, CYP2R1, group-specific component ( GC ) and vitamin D nuclear receptor ( VDR )) with body mass index (BMI) and body weight. Per allele beta (β) estimates were calculated for this association using linear regression models, controlling for age, square of age, menopausal status and sample sets. Overall, only two SNPs (rs2248359 in CYP24A1 and rs10832313 in CYP2R1 ) had a nominally significant association with BMI and weight ( P