title: Total 25-hydroxyvitamin D levels predict fracture risk: results from the 15-year follow-up of the Japanese Population-based Osteoporosis (JPOS) Cohort Study.
abstract: We found that community-dwelling women with 25-hydroxyvitamin D levels <20 ng/mL compared to levels ≥20 ng/mL indicated increased risks for clinical, non-vertebral, and fragility fractures during 5 years. Furthermore, the increased risks of non-vertebral fractures remained significant in 10 and 15 years after adjusting for age and bone mineral density.
  
  
  
  We examined whether total 25-hydroxyvitamin D (25[OH]D) levels are associated with fracture risk over 15 years in a Japanese female cohort.
  
  
  
  Of 1437 community-dwelling women aged ≥50 years in the baseline survey, 1236 provided information regarding fractures during a 15-year follow-up period. The analysis included 1211 women without early menopause or diseases affecting bone metabolism.
  
  
  
  Over 15 years, 269 clinical (224 non-vertebral, 149 fragility) fracture events were confirmed. Incidence rates categorized by 25(OH)D levels (<10, 10-20, 20-30, and ≥30 ng/mL) indicated a significant divergence for any clinical fractures in 5 years (log rank test p = 0.016) and for non-vertebral fractures in 5, 10, and 15 years (p < 0.001, p = 0.001, p = 0.017, respectively). Hazard ratios (HRs) for 25(OH)D levels <10 and 10-20 ng/mL compared to levels ≥30 ng/mL during 5 years indicated significances for clinical fractures (HR 4.93 with p = 0.009, HR 3.00 with p = 0.034) and for non-vertebral fractures (HR 6.55 with p = 0.005, HR 3.49 with p = 0.036). Those with levels <20 ng/mL compared to those with levels ≥20 ng/mL indicated significant increased risks for clinical fractures (HR 1.72 with p = 0.010), non-vertebral fractures (HR 2.45 with p < 0.001), and fragility fractures (HR 2.00 with p = 0.032) in 5 years. The HR of non-vertebral fractures for levels <20 ng/mL remained significant during 15 years (HR 1.42 with p = 0.012) after adjustment for age and femoral neck bone mineral density.
  
  
  
  Low 25(OH)D levels, especially <20 ng/mL, were associated with elevated fracture risks in Japanese women.
authors.affiliation: Department of Hygiene and Public Health, Osaka Medical College, 2-7 Daigaku-Machi, Takatsuki, Osaka, 569-8686, Japan. jtamaki@osaka-med.ac.jp.
authors.forename: J
authors.identifier: 0000-0003-3930-9729
authors.initials: J
authors.lastname: Tamaki
authors.affiliation: Department of Public Health, Faculty of Medicine, Kindai University, 377-2 Oono-higashi, Osakasayama, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Iki
authors.affiliation: Department of Human Life, Jin-ai University, 3-1-1 Ohdecho, Echizen, Fukui, 915-8586, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Sato
authors.affiliation: Department of Public Health and Home Nursing, Graduate School of Medical Sciences, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi, 461-8673, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Kajita
authors.affiliation: Nippon Express Co., Inc. Toyama, 1-2-9 Takara-cho, Toyama, 930-0007, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nishino
authors.affiliation: Department of Blood Purification and Internal Medicine, Kidney Center, Tokyo Women's Medical University, 8-1 Kawada-cho Shinjuku-ku, Tokyo, 162-8666, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Akiba
authors.affiliation: Fuji Memorial Institute of Medical Sciences, University of Tokushima, 3-18-15 Kuramoto-cho, Tokushima, 770-8503, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Matsumoto
authors.affiliation: University of Toyama, 2630 Sugitani, Toyama-shi, Toyama, 930-0194, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Kagamimori
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D049628:Body Size / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D005272:Femur Neck / Q000503:physiopathology; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D008159:Lumbar Vertebrae / Q000503:physiopathology; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood* / Q000453:epidemiology / Q000503:physiopathology; D058866:Osteoporotic Fractures / Q000097:blood* / Q000453:epidemiology / Q000503:physiopathology; D011237:Predictive Value of Tests; D018570:Risk Assessment / Q000379:methods; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
chemical_list: D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: 25-Hydroxyvitamin D; Fracture; Japanese women; Prospective cohort study