Ex-smokers and risk of hip fracture.

OBJECTIVES: The purpose of this study was to examine the reversibility of the effect of smoking on hip fracture incidence rates. METHODS: A 3-year follow-up cohort study was conducted involving 35,767 adults 50 years of age or older. Of these individuals, 421 suffered a hip fracture. RESULTS: Among participants less than 75 years of age, the relative risk (RR) of hip fracture was elevated for ex-smokers, even for those who had quit smoking more than 5 years previously (men: RR = 4.4, 95% confidence interval [CI] = 1.2, 15.3; women: RR = 1.3, 95% CI = 0.6, 3.0), but was not as high as that for current smokers (men: RR = 5.0, 95% CI = 1.5, 16.9; women: RR = 1.9, 95% CI = 1.2, 3.1). CONCLUSIONS: The effect of smoking on risk of hip fracture was not reversed completely 5 years after smoking cessation.