title: The prevalence of hemorrhoids in adults.
abstract: BACKGROUND
  Exact data on the prevalence of hemorrhoids are rare. Therefore, we designed a study to investigate the prevalence of hemorrhoids and associated risk factors in an adult general population.
  
  
  METHODS
  Between 2008 and 2009, consecutive patients were included in a prospective study. They attended the Austrian national wide health care program for colorectal cancer screening at four medical institutions. A flexible colonoscopy and detailed examination were conducted in all patients. Hemorrhoids were defined according to a standardized grading system. Independent variables included baseline characteristics, sociodemographic data, and health status. Potential risk factors were calculated by univariate and multivariate analysis.
  
  
  RESULTS
  Of 976 participants, 380 patients (38.93%) suffered from hemorrhoids. In 277 patients (72.89%), hemorrhoids were classified as grade I, in 70 patients (18.42%) as grade II, in 31 patients (8.16%) as grade III, and in 2 patients (0.53%) as grade IV. One hundred seventy patients (44.74%) complained about symptoms associated with hemorrhoids, whereas 210 patients (55.26%) reported no symptoms. In the univariate and multivariate analysis, body mass index (BMI) had a significant effect on the occurrence of hemorrhoids with p = 0.0391 and p = 0.0282, respectively. Even when correcting for other potential risk factors, an increase in the BMI of one increased the risk of hemorrhoids by 3.5%.
  
  
  CONCLUSIONS
  Hemorrhoids occur frequently in the adult general population. Notably, a considerable number of people with hemorrhoids do not complain about symptoms. In addition, a high BMI can be regarded as an independent risk factor for hemorrhoids.
authors.affiliation: Department of Surgery, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria. stefan.riss@meduniwien.ac.at
authors.forename: Stefan
authors.initials: S
authors.lastname: Riss
authors.forename: Friedrich Anton
authors.initials: FA
authors.lastname: Weiser
authors.forename: Katrin
authors.initials: K
authors.lastname: Schwameis
authors.forename: Thomas
authors.initials: T
authors.lastname: Riss
authors.forename: Martina
authors.initials: M
authors.lastname: Mittlböck
authors.forename: Gottfried
authors.initials: G
authors.lastname: Steiner
authors.forename: Anton
authors.initials: A
authors.lastname: Stift
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001317:Austria / Q000453:epidemiology; D005260:Female; D006484:Hemorrhoids / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D055815:Young Adult