Does vitamin D affect the association between rs9939609 polymorphism and depression?

: Depression is a highly prevalent and multifactorial psychological disorder. Fat Mass and Obesity-Associated () gene and the serum vitamin D level are proposed to be involved in pathophysiology of depression. This study aimed to investigate the interactions between one gene single nucleotide polymorphism, depression, and serum vitamin D level in overweight adults.: One hundred and ninety-seven overweight adults were recruited in this cross-sectional study. FTO genotyping was performed by amplification refractory mutation system polymerase chain reaction (ARMS-PCR). Depression severity was assessed using Beck's depression inventory (BDI-II). Serum vitamin D levels were measured using a direct competitive enzyme-linked immunosorbent assay (ELISA) method.: A-allele carriers had higher Beck's depression score (P = 0.03). Multivariate regression models showed a positive association between the A-allele of rs9939609 polymorphism and depression. Serum vitamin D level had no effect on the association between FTO genotype and depression.: A-allele of rs9939609 polymorphism might be associated with depression independent of serum vitamin D level. Further longitudinal studies are needed to confirm these results.