Associations of serum sex hormone-binding globulin and sex hormone concentrations with hip fracture risk in postmenopausal women.
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.
Lee
Jennifer S
JS
Division of Endocrinology, Clinical Nutrition, and Vascular Medicine, Department of Internal Medicine, University of California-Davis, Sacramento, CA 95817, USA. jswlee@ucdavis.edu.
LaCroix
Andrea Z
AZ
Wu
LieLing
L
Cauley
Jane A
JA
Jackson
Rebecca D
RD
Kooperberg
Charles
C
Leboff
Meryl S
MS
Robbins
John
J
Lewis
Cora E
CE
Bauer
Douglas C
DC
Cummings
Steven R
SR
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*
D012739:Gonadal Steroid Hormones; D012738:Sex Hormone-Binding Globulin