title: Associations of serum sex hormone-binding globulin and sex hormone concentrations with hip fracture risk in postmenopausal women.
abstract: BACKGROUND
  Endogenous estradiol, testosterone, and SHBG may influence the risk of hip fracture.
  
  
  METHODS
  From the Women's Health Initiative Observational Study, 39,793 eligible postmenopausal women did not have a previous hip fracture and were not using estrogen or other bone-active therapies. Of these, 400 who had a first-time nonpathological hip fracture (median follow-up, 7 yr) were matched to 400 controls by age, ethnicity, and baseline blood draw date. Estradiol, testosterone, and SHBG were measured in banked baseline serum.
  
  
  RESULTS
  Compared with women in the lowest tertiles, those with bioavailable testosterone in the highest tertile had a lower risk [odds ratio (OR) = 0.62; 95% confidence interval (CI) = 0.44-0.88]; those with bioavailable estradiol in the highest tertile had a lower risk (OR = 0.44; 95% CI = 0.29-0.66), and those with SHBG in the highest tertile had a higher risk (OR = 1.90; 95% CI = 1.31-2.74) of hip fracture. In models with all three hormones and potential confounders, high SHBG remained a strong independent risk factor (OR = 1.76; 95% CI = 1.12-2.78), high bioavailable testosterone remained protective (OR = 0.64; 95% CI = 0.40-1.00), but estradiol no longer was associated (OR = 0.72; 95% CI = 0.42-1.23).
  
  
  CONCLUSIONS
  High serum SHBG is associated with an increased risk of subsequent hip fracture and high endogenous testosterone with a decreased risk, independent of each other, serum estradiol concentration, and other putative risk factors. But endogenous estradiol has no independent association with hip fracture.
authors.affiliation: Division of Endocrinology, Clinical Nutrition, and Vascular Medicine, Department of Internal Medicine, University of California-Davis, Sacramento, CA 95817, USA. jswlee@ucdavis.edu.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Lee
authors.forename: Andrea Z
authors.initials: AZ
authors.lastname: LaCroix
authors.forename: LieLing
authors.initials: L
authors.lastname: Wu
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Jackson
authors.forename: Charles
authors.initials: C
authors.lastname: Kooperberg
authors.forename: Meryl S
authors.initials: MS
authors.lastname: Leboff
authors.forename: John
authors.initials: J
authors.lastname: Robbins
authors.forename: Cora E
authors.initials: CE
authors.lastname: Lewis
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Bauer
authors.forename: Steven R
authors.initials: SR
authors.lastname: Cummings
mesh_terms: D000368:Aged; D015519:Bone Density; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006620:Hip Fractures / Q000097:blood / Q000209:etiology*; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause / Q000097:blood*; D012307:Risk Factors; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*
chemical_list: D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin