title: Epidemiology of constipation in North America: a systematic review.
abstract: OBJECTIVE
  The aim of this study was to systematically review the published literature regarding prevalence, risk factors, incidence, natural history, and the effect on quality of life of constipation in North America.
  
  
  METHODS
  A computer-assisted search of MEDLINE, EMBASE, and Current Contents databases was performed independently by two investigators. Study selection criteria included the following: (1) North American population-based sample of adults with constipation; (2) publication in full manuscript form in English; and (3) report on the prevalence, incidence, and natural history of constipation or impact of constipation on quality of life. Eligible articles were reviewed in a duplicate, independent manner. Data extracted were compiled in tables and presented in descriptive form.
  
  
  RESULTS
  The estimates of the prevalence of constipation in North America ranged from 1.9% to 27.2%, with most estimates from 12% to 19%. Prevalence estimates by gender support a female-to-male ratio of 2.2:1. Constipation appears to increase with increasing age, particularly after age 65. No true population-based incidence studies or natural history studies were identified. In one cohort, 89% of patients with constipation still reported constipation at 14.7 months follow-up. From limited data, quality of life appears to be diminished by constipation, but the clinical significance of this is unclear.
  
  
  CONCLUSIONS
  Constipation is very common, as approximately 63 million people in North America meet the Rome II criteria for constipation. Minimal data are available regarding incidence, natural history, and quality of life in patients with constipation. Effort should be expended toward the study of these topics, particularly in the elderly, who are disproportionately affected by this condition.
authors.affiliation: Department of Internal Medicine, University of Michigan Division of Gastroenterology, Ann Arbor, Michigan, USA.
authors.forename: Peter D R
authors.initials: PD
authors.lastname: Higgins
authors.forename: John F
authors.initials: JF
authors.lastname: Johanson
mesh_terms: D003248:Constipation / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D009656:North America / Q000453:epidemiology; D015995:Prevalence; D011788:Quality of Life