Clin Osteol 2003; 8(4): 119-122

The role of calcitriol on bone mineral density in osteopenic women and its relationship to vitamin D receptor gene polymorphismArticles

K. Zajíčková, I. Žofková, M. Hill

The aim of the current prospective study was to evaluate the effect of calcitriol on bone mass in osteopenic women and whether this effect depends on the vitamin D receptor (VDR) gene polymorphisms.

Method: The study cohort consists of 35 women (27 of them were postmenopausal, age 68.96 ± 8.85 years) who underwent DXA measurement and were found osteopenic at the lumbar spine (T-score -1.24 ± 0.90) and/or at the hip (T-score -1.39 ± 0.75). All probands received calcitriol (0.25-0.50 pg per day) with calcium (500 mg). Bone mineral density (BMD) was measured at the baseline and during the second year of the treatment. Four single nucleotide polymorphisms (FokI, BsmI, ApaI a TaqI) in the VDR gene were assessed by a restriction analysis of PCR product.

Results: Calcitriol significantly increased BMD both at the lumbar spine (ABMD, p < 0.002) and at the hip (ABMD, p < 0.02). The gain of bone mass at the lumbar spine was associated with TaqI polymorphism in the VDR gene. Women with at least one t allele (tt+Tt genotypes) reached significant­ ly lower BMD than women without this allele (TT genotype) (p < 0.03, ANCOVA). The relationship between the remaining VDR genotypes and the BMD change was not found.

Conclusion: Our pilot results confirm calcitriol to be an effective treatment for osteopenia. The pharmacological response is modified by TaqI genoty­ pes. Whether TaqI polymorphism is responsible for the variance in response to calcitriol needs to be confirmed at the end of the 3-year treatment.

Keywords: calcitriol, osteopeniaVDR gene, TaqI polymorphism, pharmacogenetics.

Published: December 11, 2003  Show citation