title: Subclinical thyroid dysfunction and incident hip fracture in older adults.
abstract: BACKGROUND
  Subclinical thyroid dysfunction is common in older adults and affects bone metabolism, but its effects on fracture risk have not been reported. We sought to determine prospectively whether older men and women with subclinical hyperthyroidism or hypothyroidism have an increased risk of hip fracture.
  
  
  METHODS
  Prospective cohort of 3567 US community-dwelling adults, 65 years or older, with biochemically defined subclinical thyroid dysfunction or euthyroidism was enrolled from June 10, 1989, through May 30, 1990, and followed up through 2004. Main outcome measures included incidence and hazard ratios (HRs), with 95% confidence intervals (CIs), of confirmed incident hip fractures for groups with subclinical hypothyroidism, subclinical hyperthyroidism, and euthyroidism as defined at baseline.
  
  
  RESULTS
  During 39 952 person-years (median follow-up, 13 years), hip fracture incidence (per 1000 men-years) was 13.65 in men with subclinical hyperthyroidism (n = 29) and 10.27 in men with subclinical hypothyroidism (n = 184), both greater than 5.0 in men with euthyroidism (n = 1159). Men with subclinical hypothyroidism had a multivariable-adjusted HR of 2.31 (95% CI, 1.25-4.27); those with subclinical hyperthyroidism, 3.27 (0.99-11.30). After excluding those with baseline use of thyroid-altering medications, men with endogenous subclinical hyperthyroidism had a higher HR of 4.91 (95% CI, 1.13-21.27), as did men with endogenous subclinical hypothyroidism (2.45, 1.27-4.73). Hip fracture incidence (per 1000 women-years) was 8.93 in women with subclinical hypothyroidism (n = 359) and 10.90 in women with subclinical hyperthyroidism (n = 142) compared with 10.18 in women with euthyroidism (n = 1694). No clear association between subclinical dysfunction and fracture was observed in women.
  
  
  CONCLUSIONS
  Older men with subclinical hyperthyroidism or hypothyroidism are at increased risk for hip fracture. Whether treatment of the subclinical syndrome reduces this risk is unknown.
authors.affiliation: Department of Internal Medicine, University of California, Davis, Sacramento, 95817, USA. jswlee@ucdavis.edu
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Lee
authors.forename: Petra
authors.initials: P
authors.lastname: Buzková
authors.forename: Howard A
authors.initials: HA
authors.lastname: Fink
authors.forename: Joseph
authors.initials: J
authors.lastname: Vu
authors.forename: Laura
authors.initials: L
authors.lastname: Carbone
authors.forename: Zhao
authors.initials: Z
authors.lastname: Chen
authors.forename: Jane
authors.initials: J
authors.lastname: Cauley
authors.forename: Doug C
authors.initials: DC
authors.lastname: Bauer
authors.forename: Anne R
authors.initials: AR
authors.lastname: Cappola
authors.forename: John
authors.initials: J
authors.lastname: Robbins
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006620:Hip Fractures / Q000453:epidemiology*; D006801:Humans; D006980:Hyperthyroidism / Q000453:epidemiology*; D007037:Hypothyroidism / Q000453:epidemiology*; D015994:Incidence; D008297:Male; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D013972:Thyrotropin / Q000097:blood; D014481:United States / Q000453:epidemiology
chemical_list: D013972:Thyrotropin