title: Smoking and the risk of fracture in older men.
abstract: The role of smoking on fracture risk in older men was studied within a longitudinal population-based cohort study. Using time-dependent exposure information and analysis, smoking was detected to be a stronger, dose-dependent and a more long lasting risk factor for fracture than has previously been estimated.
  
  
  BACKGROUND
  Although several studies have indicated a negative influence of smoking on fracture risk in women, there are few studies in men. No study in either sex has considered that smoking exposure may vary during follow-up in a cohort study. There is a need for a prospective study with repeated measures to analyze smoking exposure and fracture risk in men.
  
  
  METHODS
  A total of 2322 men, 49-51 years of age, were enrolled in a longitudinal, population-based cohort study. Smoking status and other lifestyle habits were established at baseline and additionally at 60, 70, and 77 years of age. One or more fractures were documented in 272 men during 30 years of follow-up. Cox proportional hazards regression was used to determine the rate ratio (RR) of fracture according to time-dependent smoking habits and covariates.
  
  
  RESULTS
  The overall adjusted fracture risk was increased in current (RR, 2.71; 95% CI, 1.86-3.95) and former smokers (RR, 1.66, 95% CI; 1.18-2.34), and persistent until 30 years after cessation. Among current smokers, the adjusted risk of any fracture increased by 30% (95% CI, 6-58%) for every 5 g of tobacco smoked each day. Smoking duration did not substantially influence fracture risk in either current or former smokers. One-half (52%; 95% CI, 35-65%) of all fractures were attributable to current smoking.
  
  
  CONCLUSIONS
  Tobacco smoking seems to be a long-lasting major risk factor for fracture in older men, and the risks depends both on recency of smoking and on the daily amount of tobacco smoked, rather than smoking duration.
authors.affiliation: Section of Orthopedics, Department of Surgical Sciences, University Hospital, Uppsala, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Olofsson
authors.forename: Liisa
authors.initials: L
authors.lastname: Byberg
authors.forename: Rawya
authors.initials: R
authors.lastname: Mohsen
authors.forename: Hakan
authors.initials: H
authors.lastname: Melhus
authors.forename: Hans
authors.initials: H
authors.lastname: Lithell
authors.forename: Karl
authors.initials: K
authors.lastname: Michaëlsson
mesh_terms: D000368:Aged; D001842:Bone and Bones / Q000293:injuries*; D015331:Cohort Studies; D005500:Follow-Up Studies; D050723:Fractures, Bone / Q000453:epidemiology*; D006620:Hip Fractures / Q000453:epidemiology; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012907:Smoking