title: Long-term dietary vitamin D intake and risk of fracture and osteoporosis: a longitudinal cohort study of Swedish middle-aged and elderly women.
abstract: BACKGROUND
  The importance of dietary vitamin D for osteoporotic fracture prevention is uncertain.
  
  
  OBJECTIVE
  Our objective was to investigate associations between dietary vitamin D intake with risk of fracture and osteoporosis.
  
  
  METHODS
  In the population-based Swedish Mammography Cohort (including 61 433 women followed for 19 years), diet was assessed by repeated food frequency questionnaires.
  
  
  METHODS
  The study was conducted in 2 municipalities in central Sweden.
  
  
  METHODS
  Incident fractures were identified from registry data. In a subcohort (n = 5022), bone mineral density was determined by dual-energy x-ray absorptiometry and serum 25-hydroxyvitamin D was measured using HPLC-tandem mass spectrometry.
  
  
  RESULTS
  A total of 14 738 women experienced any type of first fracture during follow-up, and 3871 had a hip fracture. Multivariable-adjusted hazard ratio (HR) for any first fracture was 0.96 (95% confidence interval, 0.92-1.01) for the lowest (mean, 3.1 μg/d) and 1.02 (0.96-1.07) for the highest (mean, 6.9 μg/d) quintile compared with the third quintile of vitamin D intake. The corresponding HR for a first hip fracture was 1.02 (0.96-1.08) for the lowest and 1.14 (1.03-1.26) for the highest quintile. Intakes >10 μg/d, compared with <5 μg/d, conferred an HR of 1.02 (0.92-1.13) for any fracture and an HR of 1.27 (1.03-1.57) for hip fracture. The intake of vitamin D did not affect the odds for osteoporosis, although higher levels were associated with higher bone mineral density (0.3%-2%, P < .0001). A positive association was observed between vitamin D intake and serum 25-hydroxyvitamin D.
  
  
  CONCLUSIONS
  Dietary intakes of vitamin D seem of minor importance for the occurrence of fractures and osteoporosis in community-dwelling Swedish women.
authors.affiliation: Department of Surgical Sciences (G.S., L.B., E.W.L., K.M., H.Ma.), Section of Orthopedics; Department of Medical Sciences (H.Me.), Section of Clinical Pharmacology; and Department of Surgical Sciences (R.G.), Section of Anesthesiology and Intensive Care, Uppsala University, SE-751 85 Uppsala, Sweden; and Department of Nutritional Epidemiology (A.W.), Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden.
authors.forename: Greta
authors.initials: G
authors.lastname: Snellman
authors.forename: Liisa
authors.initials: L
authors.lastname: Byberg
authors.forename: Eva Warensjö
authors.initials: EW
authors.lastname: Lemming
authors.forename: Håkan
authors.initials: H
authors.lastname: Melhus
authors.forename: Rolf
authors.initials: R
authors.lastname: Gedeborg
authors.forename: Hans
authors.initials: H
authors.lastname: Mallmin
authors.forename: Alicja
authors.initials: A
authors.lastname: Wolk
authors.forename: Karl
authors.initials: K
authors.lastname: Michaëlsson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004034:Diet Surveys; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology*; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D009752:Nutritional Status; D010024:Osteoporosis / Q000453:epidemiology*; D012307:Risk Factors; D013548:Sweden / Q000453:epidemiology; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D014807:Vitamin D