Serum 25-hydroxyvitamin D, bone mineral density, and non-vertebral fracture risk in community-dwelling older men: results from Mr. Os, Hong Kong

Abstract

The study examined vitamin D status in relation to bone mineral density (BMD) and fracture risk in older Chinese men. Vitamin D deficiency was uncommon in this sample. Higher serum vitamin D level was associated with higher baseline BMD, but was not associated with bone loss or fracture risk. Vitamin D status in relation to bone health and fracture risk in Asian men is unknown. This study examined how vitamin D status was associated with BMD and fracture risk in Chinese men. The study consisted of a cross-sectional and longitudinal design (the 4-year follow-up). Subjects included 939 and 712 men aged 65year and older for cross-sectional analysis and longitudinal analysis, respectively. Baseline serum 25-hydroxyvitamin D (25OHD) was measured by a competitive radioimmunoassay kit. Baseline and 4-year percentage change in BMD at total hip, spine, and femoral neck was examined by dual-energy X-ray absorptiometry. Data on incident non-vertebral fractures and hip fractures in 4years were collected. Data were collected for confounding factors: demographics, smoking, alcohol use, body mass index, physical activity, diet, season of blood measurement, and serum parathyroid hormone level. Multivariate regression analyses were performed with adjustments for confounding factors. A total of 94.1% of this sample had serum 25OHD at 50nmol/L and over. After adjustment for potential confounding factors, higher serum 25OHD level was associated with higher baseline BMD at all measured sites. No association was observed between serum 25OHD level and percentage change in BMD or risk of non-vertebral fracture or hip fracture after adjustment for confounding factors. Vitamin D deficiency was not common in this sample of Chinese men. Higher serum 25OHD level was associated with higher BMD at cross-sectional level. There was no association between serum 25OHD level and bone loss or fracture risk.