CORRELATION BETWEEN VITAMNIN-D RECEPTOR GENOTYPES AND BONE-MINERAL DENSITY IN JAPANESE PATIENTS WITH OSTEOPOROSIS

In order to better understand the pathogenesis of osteoporosis, we inv estigated the correlation between the vitamin D receptor (VDR) genotyp es defined by BsmI restriction enzyme, as well as other related factor s, and the bone mineral density (BMD) at the lumbar spine in 90 Japane se patients with osteoporosis. The same study was performed in 36 pati ents with osteoarthrosis of the hip joint and 92 healthy volunteers. T he majority of the VDR genotypes were bb, and a few of the population showed either the BE or Bb genotype in all three groups. There was no statistical sro difference in the frequencies of these VDR genotypes i n the three groups, The mean age-matched value of BMD (Z scores) at th e lumbar spine in patients with osteoporosis was significantly lower t han that in patients with osteoarthrosis or healthy volunteers. The me an Z scores of the healthy volunteers with bb genotype were significan tly higher than those with BE genotype, whereas those of the osteoporo sis patients with BE genotype were significantly higher than those wit h Bb genotype. There was no significant difference in the mean Z score s between bb and Bb genotypes in patients with osteoporosis and health y volunteers, No significant difference was seen in the mean Z scores in patients with osteoarthrosis regardless of genotype. On the other h and, body weight significantly correlated with BMD in patients with os teoporosis by simple- and multiple-regression analysis. These results indicate that the BMD at the lumbar spine in Japanese patients with os teoporosis is affected by body weight, and might be affected partially by the VDR genotypes defined by BsmI.