title: Calcium, vitamin D, milk consumption, and hip fractures: a prospective study among postmenopausal women.
abstract: BACKGROUND
  Short trials of calcium supplementation show that it reduces loss of bone density in postmenopausal women; longer observational studies do not generally find a lower risk of hip fracture with higher-calcium diets. Fewer studies have focused on vitamin D in preventing postmenopausal osteoporosis or fractures.
  
  
  OBJECTIVE
  We assessed relations between postmenopausal hip fracture risk and calcium, vitamin D, and milk consumption.
  
  
  METHODS
  In an 18-y prospective analysis in 72 337 postmenopausal women, dietary intake and nutritional supplement use were assessed at baseline in 1980 and updated several times during follow-up. We identified 603 incident hip fractures resulting from low or moderate trauma. Relative risks (RRs) from proportional hazards models were controlled for other dietary and nondietary factors.
  
  
  RESULTS
  Women consuming > or = 12.5 microg vitamin D/d from food plus supplements had a 37% lower risk of hip fracture (RR = 0.63; 95% CI: 0.42, 0.94) than did women consuming < 3.5 microg/d. Total calcium intake was not associated with hip fracture risk (RR = 0.96; 95% CI: 0.68, 1.34 for > or = 1200 compared with < 600 mg/d). Milk consumption was also not associated with a lower risk of hip fracture (P for trend = 0.21).
  
  
  CONCLUSIONS
  An adequate vitamin D intake is associated with a lower risk of osteoporotic hip fractures in postmenopausal women. Neither milk nor a high-calcium diet appears to reduce risk. Because women commonly consume less than the recommended intake of vitamin D, supplement use or dark fish consumption may be prudent.
authors.affiliation: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA. diane.feskanich@channing.harvard.edu
authors.forename: Diane
authors.initials: D
authors.lastname: Feskanich
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: Graham A
authors.initials: GA
authors.lastname: Colditz
mesh_terms: D000818:Animals; D015519:Bone Density / Q000187:drug effects*; D002136:Calcium, Dietary / Q000008:administration & dosage*; D015331:Cohort Studies; D004032:Diet; D019587:Dietary Supplements; D005260:Female; D006620:Hip Fractures / Q000453:epidemiology* / Q000517:prevention & control; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D008892:Milk / Q000737:chemistry; D015663:Osteoporosis, Postmenopausal / Q000453:epidemiology / Q000517:prevention & control; D017698:Postmenopause; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D002136:Calcium, Dietary; D014807:Vitamin D