Serum 25-hydroxyvitamin D concentrations in Japanese postmenopausal women with osteoporotic fractures

OBJECTIVES: To assess the vitamin D status in postmenopausal women with osteoporotic fractures, determine its concentration by fracture site at the clinical setting, and compare the proportion of vitamin D deficiency with that reported in literature. METHODS: The prospective study included 317 postmenopausal women with osteoporotic fractures who were treated consecutively from 2016 to 2018. After obtaining informed consent for participation in the seamless treatment of osteoporosis against fractures study, which is our initiative to prevent secondary osteoporotic fractures, we registered the patients, examined bone mineral density (BMD) at the unfractured femoral neck and lumbar spine, serum 25-hydroxyvitamin D (25(OH)D) concentration, blood chemistry, and bone turnover markers. RESULTS: The mean age of the patients was 80.7 years. Moreover, 78% of patients of all fractures had 25(OH)D concentration < 20 ng/mL, whereas 12% of patients had 25(OH)D concentration ≥ 30 ng/mL 25(OH)D concentration in hip fractures was significantly lower than that in vertebral or distal radius fractures (P < 0.05). Multiple regression analysis revealed that 25(OH)D concentration is significantly associated with femoral neck BMD (β = 0.16; 95% confidence interval [CI], 0.78–12.17, P = 0.03) and serum albumin concentration (β = 0.21; 95% CI, 0.62–2.96, P < 0.001) in patients with 25(OH)D concentration < 30 ng/mL. CONCLUSIONS: The results of this study show that the proportion of postmenopausal women with osteoporotic fractures who had vitamin D deficiency was higher than the proportion in previous reports that examined general postmenopausal women (35.2%–52.0%).