title: Prevalence of complementary and alternative medicine (CAM) use by the general population: a systematic review and update.
abstract: OBJECTIVE
  To update previous systematic reviews of 12-month prevalence of complementary and alternative medicine (CAM) use by general populations; to explore trends in CAM use by national populations; to develop and apply a brief tool for assessing methodological quality of published CAM-use prevalence surveys.
  
  
  METHODS
  Nine databases were searched for published studies from 1998 onwards. Studies prior to 1998 were identified from two previous systematic reviews. A six-item literature-based tool was devised to assess robustness and interpretability of CAM-use estimates.
  
  
  RESULTS
  Fifty-one reports from 49 surveys conducted in 15 countries met the inclusion criteria. We extracted 32 estimates of 12-month prevalence of use of any CAM (range 9.8-76%) and 33 estimates of 12-month prevalence of visits to CAM practitioners (range 1.8-48.7%). Quality of methodological reporting was variable; 30/51 survey reports (59%) met four or more of six quality criteria. Estimates of 12-month prevalence of any CAM use (excluding prayer) from surveys using consistent measurement methods showed remarkable stability in Australia (49%, 52%, 52%; 1993, 2000, 2004) and USA (36%, 38%; 2002, 2007).
  
  
  CONCLUSIONS
  There was evidence of substantial CAM use in the 15 countries surveyed. Where national trends were discernable because of consistent measurement, there was no evidence to suggest a change in 12-month prevalence of CAM use since the previous systematic reviews were published in 2000. Periodic surveys are important to monitor population-level CAM use. Use of government-sponsored health surveys may enhance robustness of population-based prevalence estimates. Comparisons across countries could be improved by standardising approaches to data collection.
authors.affiliation: Cardiff School of Health Sciences, Cardiff Metropolitan University, Cardiff, UK. peharris@cardiffmet.ac.uk
authors.forename: P E
authors.initials: PE
authors.lastname: Harris
authors.forename: K L
authors.initials: KL
authors.lastname: Cooper
authors.forename: C
authors.initials: C
authors.lastname: Relton
authors.forename: K J
authors.initials: KJ
authors.lastname: Thomas
mesh_terms: D000328:Adult; D002648:Child; D000529:Complementary Therapies / Q000706:statistics & numerical data*; D014943:Global Health; D006306:Health Surveys / Q000592:standards; D006801:Humans; D010342:Patient Acceptance of Health Care / Q000706:statistics & numerical data*; D012107:Research Design