title: Association of quantity and duration of smoking with erectile dysfunction: a dose-response meta-analysis.
abstract: BACKGROUND
  Some original studies and a recent meta-analysis suggested that smoking could be associated with the risk of erectile dysfunction (ED), but the dose-response relationship between them was unclear.
  
  
  OBJECTIVE
  The aim of this study was to investigate the potential association between quantity and duration of smoking and the risk of ED.
  
  
  METHODS
  We conducted a literature search of PubMed, Embase, Web of Science, and Scopus from these databases' inception through March 2014 for observational epidemiological studies examining the association between smoking and risk of ED. Random-effects meta-analyses were used to combine the results of included studies.
  
  
  METHODS
  Quantitative review of published observational epidemiological studies on the association between smoking and risk of ED was the main outcome measure.
  
  
  RESULTS
  One cohort study and nine cross-sectional studies were eligible for inclusion in the meta-analysis (50,360 participants and 12,218 cases with ED). No evidence of a curve linear association was observed between smoking and risk of ED. The summary odds ratio of ED for an increase of 10 cigarettes smoked per day was 1.14 (95% confidence interval 1.09 to 1.18), with moderate heterogeneity (P = 0.061, I(2)  = 44.7%). For an increment of 10 years of smoking, the combined odds ratios of ED was 1.15 (95% confidence interval 1.10 to 1.19), without substantial heterogeneity (P = 0.522, I(2)  = 0.0%).
  
  
  CONCLUSIONS
  Evidence from observational studies suggests that there is a positive dose-response association between quantity and duration of smoking and risk of ED.
authors: School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors: Shiyi
authors: S
authors: Cao
authors: Yong
authors: Y
authors: Gan
authors: Xiaoxin
authors: X
authors: Dong
authors: Junan
authors: J
authors: Liu
authors: Zuxun
authors: Z
authors: Lu
mesh_terms: D000328:Adult; D007172:Erectile Dysfunction / Q000209:etiology*; D006801:Humans; D008297:Male; D016017:Odds Ratio; D012306:Risk; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology*; D013997:Time Factors
keywords: Dose-Response; Erectile Dysfunction; Meta-Analysis; Smoking; Tobacco and Cigarette