Association between serum vitamin B6 concentration and risk of osteoporosis in the middle-aged and older people in China: a cross-sectional study

Objective To determine the relationship between serum vitamin B-6 (Vit B-6) concentration and the status of bone mineral density and identify the relationship between serum Vit B6 and bone metabolism parameters in middle-aged and older people in China. Design The present study was a cross-sectional study within the framework of an ongoing prospective population-based cohort study. Setting and participants A total of 1829 residents (men >= 50 years and women >= 45 years) from two subdistricts were recruited from July 2015 to February 2016 in Shanghai, China. Measures Recruited residents were grouped (control, osteopenia and osteoporosis) according to their lumbar spine bone mineral density, measured through dual-energy X-ray absorptiometry. Serum Vit B-6 concentrations, bone turnover marker concentrations and calcium and phosphorus metabolism parameters were assessed. Results No significant linear trend between serum Vit B-6 concentrations and lumbar bone mass was observed in the men. In the women, the average osteoporosis risk was 61% higher at serum Vit B-6 concentrations of < 19.2 mu g/L than at those of > 26.9 mu g/L (OR 1.61, 95% CI 1.00 to 2.58). However, there was no significance after controlling of serum 25-hydroxy-vitamin D concentration and parathyroid hormone concentration, respectively. In the osteoporotic women, the serum Vit B-6 concentration was significantly negatively correlated to concentrations of bone turnover marker including N-terminal propeptide of type I collagen, beta-C-terminal telopeptide of type I collagen and osteocalcin. It was also positively related to the serum 25-hydroxy-vitamin D concentration and inversely related to the serum parathyroid hormone concentration. Conclusions A relatively low serum Vit B-6 concentration, even in the normal range, may be a risk factor for osteoporosis in postmenopausal women, which is dependent on serum 25-hydroxy-vitamin D concentration and parathyroid hormone concentration.