Replication study of the vitamin D receptor (VDR) genotype association with skeletal muscle traits and sarcopenia.

Polymorphisms in the vitamin D receptor (VDR) gene are some of the most studied in relation to skeletal muscle traits and significant associations have been observed by multiple groups. One such paper by our group provided the first evidence of a genetic association with sarcopenia in men, but that finding has yet to be replicated in an independent cohort. In the present study, we examined multiple VDR polymorphisms in relation to skeletal muscle traits and sarcopenia in 864 men and women across the adult age span. In addition to VDR genotypes and haplotypes, measurements of skeletal muscle strength and fat-free mass (FFM) were determined in all subjects and a measure of sarcopenia was calculated. We observed significant associations between Fok1 and Bsm1 genotypes and skeletal muscle strength in men and women, though these associations were modest and no significant associations were observed for these polymorphisms and muscle mass traits nor for Bsm1-Taq1 haplotype with muscle strength. Fok1 FF genotype was associated with an increased the risk of sarcopenia in older women compared to f-allele carriers (1.3-fold higher risk). These results support previous findings that VDR genetic variation appears to impact skeletal muscle strength and risk for sarcopenia but the influence is modest.