Vitamin D status and the Cdx-2 polymorphism of the vitamin D receptor gene are determining factors of bone mineral density in young healthy postmenopausal women

Abstract

Bone mineral density (BMD) is a main determinant of osteoporotic fractures. A cross-sectional study was conducted in 229 young, healthy postmenopausal women (PMW) to evaluate the contribution of the vitamin D endocrine system and other clinical, biochemical and genetic parameters. Clinical risk factors for osteoporosis were obtained by a questionnaire. Serum concentrations of 25OHD, 1,25(OH)2D, PTH, and bone turnover markers were measured. The BsmI, FokI and Cdx-2 polymorphisms of the vitamin D receptor (VDR) gene were determined. DXA and the WHO criteria were applied for the diagnosis of osteoporosis. Univariate logistic and multivariate logistic regression analyses were carried out.

Results: The prevalence of vitamin D deficiency (<50nmol/l) was 50%. Age increased osteoporosis risk; whereas body mass index (BMI), number of reproductive years, 25OHD level and the Cdx-2 polymorphism in the VDR gene (when allele A is present) were found to be protective. Therefore, both serum 25OHD and VDR polymorphism should be taken into account in the evaluation and implementation of therapeutic strategies concerning PMW, especially as the prevalence of vitamin D deficiency is still alarmingly high even at Southern latitudes. This article is part of a Special Issue entitled 'Vitamin D Workshop'.