ApaI polymorphisms of the vitamin D receptor predict bone density of the lumbar spine and not racial difference in bone density in young men

A number of previous investigations showed significant associations between polymorphisms of the vitamin D receptor (VDR) gene and bone mineral density (BMD). BMD is influenced by hormones and the rate of skeletal remodeling. A study was performed to investigate the possible relationship between ApaI, BsmI, TaqI, and Fokl polymorphisms of the VDR gene and serum 1,25-dihydroxyvitamin D (1,25(OH)(2)D), osteocalcin, and propeptide of type I collagen (PICP)-markers of bone turnover, total body calcium, and BMD of the total body, radius, lumbar spine, trochanter, and femoral neck-in 39 young adult black men of 20 to 40 years of age and 44 age-, height-, and weight-matched white men. The distribution of each of the four alleles of the VDR genotypes was similar in the two racial groups. The ApaI VDR genotype was associated with serum PICP (P = .0494) but not with serum 1,25(OH)(2)D or serum osteocalcin. A significant association between the ApaI VDR genotype and BMD of the lumbar spine (P = .0291) was also observed. However, the BsmI, TaqI, and FokI genotypes were not significantly associated with BMD or serum osteocalcin, PICP or 1,25(OH)(2)D. Multivariate stepwise analysis indicated that (1) the ApaI VDR genotype was associated with BMD of the lumbar spine in the two groups together; with total body calcium and BMD of the total body, radius, trochanter, and femoral neck in the black men; and with BMD of the radius in the white men; analysis also indicated that (2) race was significantly associated with total body calcium and BMD of the total body, lumbar spine, and femoral neck. In summary, the ApaI VDR genotype is associated with serum PICP and BMD at a number of sites but does not contribute to or account for racial differences in BMD in young adult men.