Multiple vitamin deficiencies additively increase the risk of incident fractures in Japanese postmenopausal women.

Abstract

To evaluate the associations of multiple vitamin deficiencies on incident fractures, the relationships between serum vitamin markers and incident bone fractures were investigated in Japanese postmenopausal women. This analysis used a subset of the ongoing cohort maintained by a primary care institution. Inclusion criteria of the present study were postmenopausal women aged ≥ 50years, without vitamin supplementation and secondary osteoporosis. Baseline serum concentrations of 25-hydroxyvitamin D (25(OH)D), undercarboxylated osteocalcin (ucOC), and homocysteine (Hcy) were measured to assess vitamin D, vitamin K, and vitamin B, respectively. Since 25(OH) D positively relates to vitamin D, ucOC and Hcy negatively relate to vitamin K and vitamin B nutrients, respectively, the subjects with lower (25(OH)D) or higher (ucOC or Hcy) values than each median value was defined as subjects with the corresponding vitamin deficiency. Subjects were divided into four groups according to the number of deficiency: no deficiency, single deficiency, double deficiencies, and triple deficiencies. Relationships between the vitamin deficiencies and incident fractures were evaluated by Cox regression analysis. A total of 889 subjects were included in this analysis; their mean and SD age was 68.3 ± 9.5years, and the follow-up period was 6.3 ± 5.1years. The numbers of subjects in the four groups were 139 (15.6%), 304 (34.2%), 316 (35.5%), and 130 (14.6%) for the groups with no, single, double, and triple deficiencies, respectively. Incident fractures were observed in 264 subjects (29.7%) during the observation period. The number of deficiencies was significantly associated with incident fracture (hazard ratio 1.25, 95% confidence interval 1.04-1.50, P = 0.018) after adjustment for possible confounding factors including the treatment of osteoporosis. Accumulation of vitamin deficiencies was related to incident fractures.