title: Risk Factors for Hemorrhoids on Screening Colonoscopy.
abstract: BACKGROUND
  Constipation, a low fiber diet, sedentary lifestyle and gravidity are commonly assumed to increase the risk of hemorrhoids. However, evidence regarding these factors is limited. We examined the association between commonly cited risk factors and the prevalence of hemorrhoids.
  
  
  METHODS
  We performed a cross sectional study of participants who underwent a colonoscopy in a colorectal adenoma prevention trial and who had a detailed assessment of bowel habits, diet and activity. The presence of hemorrhoids was extracted from the subjects' colonoscopy reports. We used logistic regression to estimate odds ratios and 95% confidence intervals while adjusting for age and sex.
  
  
  RESULTS
  The study included 2,813 participants. Of these, 1,074 had hemorrhoids recorded. Constipation was associated with an increased prevalence of hemorrhoids (OR 1.43, 95% CI 1.11, 1.86). Of the fiber subtypes, high grain fiber intake was associated with a reduced risk (OR for quartile 4 versus quartile 1 = 0.78, 95% CI 0.62, 0.98). We found no association when comparing gravid and nulligravida women (OR 0.93, 95% CI 0.62-1.40). Sedentary behavior was associated with a reduced risk (OR 0.80, 95% CI 0.65-0.98), but not physical activity (OR 0.83, 95% CI 0.66-1.03). Neither being overweight nor obese was associated with the presence of hemorrhoids (OR 0.89, 95% CI 0.72-1.09 and OR 0.86, 95% CI 0.70-1.06).
  
  
  CONCLUSIONS
  Constipation is associated with an increased risk of hemorrhoids. Gravidity and physical activity do not appear to be associated. High grain fiber intake and sedentary behavior are associated with a decreased risk of hemorrhoids.
authors.affiliation: University of North Carolina School of Medicine, Chapel Hill, NC, United States of America.
authors.forename: Anne F
authors.initials: AF
authors.lastname: Peery
authors.affiliation: University of North Carolina School of Medicine, Chapel Hill, NC, United States of America.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Sandler
authors.affiliation: University of North Carolina School of Medicine, Chapel Hill, NC, United States of America.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Galanko
authors.affiliation: The University of Texas MD Anderson Cancer Center, Houston, TX, United States of America.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Bresalier
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, CA, United States of America.
authors.forename: Jane C
authors.initials: JC
authors.lastname: Figueiredo
authors.affiliation: University of Colorado Anschutz Medical Campus, Denver, CO, United States of America.
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Ahnen
authors.affiliation: Geisel School of Medicine at Dartmouth, Hanover, NH, United States of America.
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Barry
authors.affiliation: University of North Carolina School of Medicine, Chapel Hill, NC, United States of America; Geisel School of Medicine at Dartmouth, Hanover, NH, United States of America.
authors.forename: John A
authors.initials: JA
authors.lastname: Baron
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003248:Constipation / Q000453:epidemiology*; D004032:Diet / Q000009:adverse effects; D005260:Female; D006484:Hemorrhoids / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D057185:Sedentary Behavior