title: Homocysteine levels and risk of hip fracture in postmenopausal women.
abstract: BACKGROUND
  Recent studies suggest that high homocysteine levels are associated with an increased risk of fractures. Homocysteine levels are known to be influenced by vitamin B and folate supply or status, and poor renal function can result in higher levels independent of nutritional adequacy.
  
  
  OBJECTIVE
  The aim of the study was to determine the associations between fasting homocysteine levels and incident hip fractures, and the effects of other factors on hip fracture risk.
  
  
  METHODS
  We conducted a case-control study in the Women's Health Initiative Observational Study, a study of postmenopausal women (n = 93,676) recruited in the United States. We selected 400 incident cases of hip fracture and 400 controls matched on age, ethnicity, and blood draw date among women not on osteoporosis therapies. Outcome measures included physician-adjudicated, incident hip fractures. Baseline lifestyle and nutritional questionnaires were performed.
  
  
  RESULTS
  The risk of hip fracture increased 1.38-fold [95% confidence interval (CI), 1.14, 1.66] for each sd increase in serum homocysteine level after adjustment for fracture risk factors. This association was not affected by adjustment for dietary folate, B6, or B12 intake, but it diminished after adjustment for cystatin-C level (odds ratio, 1.08; 95% CI, 0.66-1.79), a measure of renal function not affected by muscle mass. Among women in the highest quartile of homocysteine and cystatin-C compared to those without elevations in either biomarker, the risk of hip fracture was substantially elevated (odds ratio, 2.8; 95% CI, 1.61-4.87).
  
  
  CONCLUSIONS
  This study indicates that high homocysteine levels are associated with an increased risk of hip fracture, which could be accounted for by poor renal function.
authors.affiliation: Brigham and Women's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA. mleboff@partners.org
authors.forename: Meryl S
authors.initials: MS
authors.lastname: Leboff
authors.forename: Rupali
authors.initials: R
authors.lastname: Narweker
authors.forename: Andrea
authors.initials: A
authors.lastname: LaCroix
authors.forename: Lieling
authors.initials: L
authors.lastname: Wu
authors.forename: Rebecca
authors.initials: R
authors.lastname: Jackson
authors.forename: Jennifer
authors.initials: J
authors.lastname: Lee
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Bauer
authors.forename: Jane
authors.initials: J
authors.lastname: Cauley
authors.forename: Charles
authors.initials: C
authors.lastname: Kooperberg
authors.forename: Cora
authors.initials: C
authors.lastname: Lewis
authors.forename: Asha M
authors.initials: AM
authors.lastname: Thomas
authors.forename: Steven
authors.initials: S
authors.lastname: Cummings
mesh_terms: D000368:Aged; D000428:Alcohol Drinking; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006620:Hip Fractures / Q000453:epidemiology*; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000150:complications*; D008875:Middle Aged; D017698:Postmenopause; D012307:Risk Factors; D012907:Smoking
chemical_list: D015415:Biomarkers; D006710:Homocysteine