title: Cultural background, non-therapeutic circumcision and the risk of meatal stenosis and other urethral stricture disease: Two nationwide register-based cohort studies in Denmark 1977-2013.
abstract: BACKGROUND
  Meatal stenosis is markedly more common in circumcised than genitally intact males, affecting 5-20 per cent of circumcised boys. However, no population-based study has estimated the relative risk of meatal stenosis and other urethral stricture diseases (USDs) or the population attributable fraction (AFp) associated with non-therapeutic circumcision.
  
  
  METHODS
  In two nationwide cohort studies (comprising 4.0 million males of all ages and 810 719 non-Muslim males aged 0-36 years, respectively), we compared hospital contact rates for USD during 1977-2013 between circumcised and intact Danish males. Hazard ratios (HRs) were obtained using Cox proportional hazards regression, and the AFpestimated the proportion of USD cases in <10 year-old boys that is due to non-therapeutic circumcision.
  
  
  RESULTS
  Muslim males had higher rates of meatal stenosis than ethnic Danish males, particularly in <10 year-old boys (HR 3.44, 95 per cent confidence interval 2.42-4.88). HRs linking circumcision to meatal stenosis (10.3, 4.53-23.4) or other USDs (5.14, 3.48-7.60) were high, and attempts to reduce potential misclassification and confounding further strengthened the association, particularly in <10 year-old boys (meatal stenosis: 26.3, 9.37-73.9; other USDs: 14.0, 6.86-28.6). Conservative calculations revealed that at least 18, 41, 78, and 81 per cent of USD cases in <10 year-old boys from countries with circumcision prevalences as in Denmark, the United Kingdom, the United States and Israel, respectively, may be attributable to non-therapeutic circumcision.
  
  
  CONCLUSIONS
  Our study provides population-based epidemiological evidence that circumcision removes the natural protection against meatal stenosis and, possibly, other USDs as well.
authors.affiliation: Statens Serum Institut, Department of Epidemiology Research, DK-2300 Copenhagen S, Denmark; Aalborg University, Department of Clinical Medicine, Center for Sexology Research, DK-9000 Aalborg, Denmark. Electronic address: mfr@ssi.dk.
authors.forename: Morten
authors.initials: M
authors.lastname: Frisch
authors.affiliation: Statens Serum Institut, Department of Epidemiology Research, DK-2300 Copenhagen S, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Simonsen
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002944:Circumcision, Male / Q000009:adverse effects* / Q000706:statistics & numerical data; D015331:Cohort Studies; D003251:Constriction, Pathologic / Q000209:etiology; D003469:Culture; D003718:Denmark / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007514:Islam; D008297:Male; D012042:Registries; D012306:Risk; D014525:Urethral Stricture / Q000209:etiology*; D055815:Young Adult
keywords: Circumcision; Complications; Epidemiology; Meatal stenosis; Urethral stricture disease