title: Hygiene and health: systematic review of handwashing practices worldwide and update of health effects.
abstract: OBJECTIVE
  To estimate the global prevalence of handwashing with soap and derive a pooled estimate of the effect of hygiene on diarrhoeal diseases, based on a systematic search of the literature.
  
  
  METHODS
  Studies with data on observed rates of handwashing with soap published between 1990 and August 2013 were identified from a systematic search of PubMed, Embase and ISI Web of Knowledge. A separate search was conducted for studies on the effect of hygiene on diarrhoeal disease that included randomised controlled trials, quasi-randomised trials with control group, observational studies using matching techniques and observational studies with a control group where the intervention was well defined. The search used Cochrane Library, Global Health, BIOSIS, PubMed, and Embase databases supplemented with reference lists from previously published systematic reviews to identify studies published between 1970 and August 2013. Results were combined using multilevel modelling for handwashing prevalence and meta-regression for risk estimates.
  
  
  RESULTS
  From the 42 studies reporting handwashing prevalence we estimate that approximately 19% of the world population washes hands with soap after contact with excreta (i.e. use of a sanitation facility or contact with children's excreta). Meta-regression of risk estimates suggests that handwashing reduces the risk of diarrhoeal disease by 40% (risk ratio 0.60, 95% CI 0.53-0.68); however, when we included an adjustment for unblinded studies, the effect estimate was reduced to 23% (risk ratio 0.77, 95% CI 0.32-1.86).
  
  
  CONCLUSIONS
  Our results show that handwashing after contact with excreta is poorly practiced globally, despite the likely positive health benefits.
authors.affiliation: Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Freeman
authors.forename: Meredith E
authors.initials: ME
authors.lastname: Stocks
authors.forename: Oliver
authors.initials: O
authors.lastname: Cumming
authors.forename: Aurelie
authors.initials: A
authors.lastname: Jeandron
authors.forename: Julian P T
authors.initials: JP
authors.lastname: Higgins
authors.forename: Jennyfer
authors.initials: J
authors.lastname: Wolf
authors.forename: Annette
authors.initials: A
authors.lastname: Prüss-Ustün
authors.forename: Sophie
authors.initials: S
authors.lastname: Bonjour
authors.forename: Paul R
authors.initials: PR
authors.lastname: Hunter
authors.forename: Lorna
authors.initials: L
authors.lastname: Fewtrell
authors.forename: Valerie
authors.initials: V
authors.lastname: Curtis
mesh_terms: D003967:Diarrhea / Q000209:etiology / Q000517:prevention & control*; D004781:Environmental Exposure / Q000517:prevention & control; D014943:Global Health; D006235:Hand Disinfection; D006801:Humans; D006920:Hygiene; D012499:Sanitation; D012915:Soaps
chemical_list: D012915:Soaps
keywords: cálculos de riesgo; diarrea; diarrhoea; diarrhée; estimations de risque; handwashing; higiene; hygiene; hygiène; lavado de manos; lavage des mains; meta-analysis; meta-análisis; méta-analyse; risk estimates