title: Smoking and risk of erectile dysfunction: systematic review of observational studies with meta-analysis.
abstract: BACKGROUND
  There are many recent observational studies on smoking and risk of erectile dysfunction (ED) and whether smoking increases the risk of ED is still inconclusive. The objective of this meta-analysis was to synthesize evidence from studies that evaluated the association between smoking and the risk of ED.
  
  
  METHODS
  We searched PubMed, Embase, Web of Science, and Scopus in January 2013 to identify cohort and case-control studies that evaluated the association between smoking and ED. Study quality of included studies was assessed by the Newcastle-Ottawa scale. Random-effects meta-analyses were used to combine the results of included studies.
  
  
  RESULTS
  Four prospective cohort studies and four case-control studies involving 28, 586 participants were included. Because of significant heterogeneity after including case-control studies in meta-analysis, the consistent results of prospective cohort studies were considered more accurate, Because of significant heterogeneity after including case-control studies in meta-analysis, the consistent results of prospective cohort studies were considered more accurate, Compared with non-smokers, the overall odd ratio of ED in prospective cohort studies was 1.51(95% CI: 1.34 to 1.71) for current smokers, and it was 1.29 (95% CI: 1.07 to 1.47) for former smokers. Evidence of publication bias was not found.
  
  
  CONCLUSIONS
  Evidence from epidemiological studies suggests that smoking, especially current smoking, may significantly increase the risk of ED.
authors.affiliation: School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
authors.forename: Shiyi
authors.initials: S
authors.lastname: Cao
authors.forename: Xiaoxu
authors.initials: X
authors.lastname: Yin
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Wang
authors.forename: Hongfeng
authors.initials: H
authors.lastname: Zhou
authors.forename: Fujian
authors.initials: F
authors.lastname: Song
authors.forename: Zuxun
authors.initials: Z
authors.lastname: Lu
mesh_terms: D016022:Case-Control Studies; D007172:Erectile Dysfunction / Q000209:etiology*; D006801:Humans; D008297:Male; D016017:Odds Ratio; D011446:Prospective Studies; D012907:Smoking / Q000009:adverse effects*