title: Cigarette smoking is associated with a reduction in the risk of incident gout: results from the Framingham Heart Study original cohort.
abstract: OBJECTIVE
  Cigarette smoking is correlated with other risk factors for gout such as adiposity and alcohol intake. The goal of this study was to study the direction and magnitude of association between cigarette smoking and risk for gout.
  
  
  METHODS
  We analysed 54-year follow-up data (1948-2002) for 2279 men and 2785 women who were gout-free at their first assessment as a part of the Framingham Heart Study. Using Cox proportional hazards models we estimated the association between cigarette smoking and incident gout among men and women separately after adjusting for age, BMI, alcohol intake, hypertension, kidney disease and diabetes.
  
  
  RESULTS
  There were 399 incident cases (249 men and 150 women) of gout over 151 058 person-years of observation. Incidence rates of gout per 1000 person-years for smokers and non-smokers were 2.13 (95% CI 1.79, 2.53) and 3.04 (95% CI 2.70, 3.42), respectively. In multivariable Cox models, cigarette smoking was associated with gout with a hazard ratio of 0.76 (95% CI 0.59, 0.98) overall, 0.68 (95% CI 0.49, 0.93) among men and 0.92 (95% CI 0.60, 1.41) among women. Lower risk for smokers was evident among all obesity categories, but not among women. Sensitivity analysis suggested that the magnitude of the true odds ratio might be lower than our calculations.
  
  
  CONCLUSIONS
  Cigarette smoking is associated with lower incidence of gout and this is not explained by differences in the prevalence of risk factors. The mechanistic underpinnings of this epidemiological finding merits further study.
authors.affiliation: Department of Immunology and Rheumatology, Stanford University School of Medicine, Palo Alto, CA, USA.
authors.forename: Weiqi
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Immunology and Rheumatology, Stanford University School of Medicine, Palo Alto, CA, USA. e.krishnan@stanford.edu.
authors.forename: Eswar
authors.initials: E
authors.lastname: Krishnan
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006073:Gout / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008297:Male; D008404:Massachusetts; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000009:adverse effects*
keywords: Framingham Heart Study; cigarette smoking; gout; risk factor; survival model