title: Smoking, surgery, and venous thromboembolism risk in women: United Kingdom cohort study.
abstract: BACKGROUND
  Evidence about the effect of smoking on venous thromboembolism risk, generally and in the postoperative period, is limited and inconsistent. We examined the incidence of venous thromboembolism in relation to smoking habits, both in the absence of surgery and in the first 12 postoperative weeks, in a large prospective study of women in the United Kingdom.
  
  
  RESULTS
  During 6 years' follow-up of 1 162 718 women (mean age 56 years), 4630 were admitted to hospital for or died of venous thromboembolism. In the absence of surgery, current smokers had a significantly increased incidence of venous thromboembolism compared with never-smokers (adjusted relative risk 1.38, 95% confidence interval 1.28-1.48), with significantly greater risks in heavier than lighter smokers (relative risks 1.47 [95% confidence interval 1.34-1.62] and 1.29 [95% confidence interval 1.17-1.42] for ≥15 versus <15 cigarettes per day). Current smokers were also more likely to have surgery than never-smokers (relative risk 1.12, 95% confidence interval 1.12-1.13). Among women who had surgery, the incidence of venous thromboembolism in the first 12 postoperative weeks was significantly greater in current than never-smokers (relative risk 1.16, 95% confidence interval 1.02-1.30).
  
  
  CONCLUSIONS
  Venous thromboembolism incidence was increased in current smokers, both in the absence of surgery and in the 12 weeks after surgery. Smoking is another factor to consider in the assessment of venous thromboembolism risk in patients undergoing surgery.
authors.affiliation: Cancer Epidemiology Unit, University of Oxford, Oxford, United Kingdom. sian.sweetland@ceu.ox.ac.uk
authors.forename: Siân
authors.initials: S
authors.lastname: Sweetland
authors.forename: Lianne
authors.initials: L
authors.lastname: Parkin
authors.forename: Angela
authors.initials: A
authors.lastname: Balkwill
authors.forename: Jane
authors.initials: J
authors.lastname: Green
authors.forename: Gillian
authors.initials: G
authors.lastname: Reeves
authors.forename: Valerie
authors.initials: V
authors.lastname: Beral
mesh_terms: D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011183:Postoperative Complications / Q000453:epidemiology*; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D006113:United Kingdom / Q000453:epidemiology; D054556:Venous Thromboembolism / Q000453:epidemiology*