This study, supported by SHARE researchers, estimates the global prevalence of handwashing with soap and derives a pooled estimate of the effect of hygiene on diarrhoeal diseases, based on a systematic search of the literature. 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); and by 23% (risk ratio 0.77, 95% CI 0.32–1.86), when adjusted for unblinded studies.
Freeman, M.C.; Stocks, M.E.; Cumming, O.; Jeandron, A.; Higgins, J.P.T.; Wolf, J.; Pruss-Ustun, A.; Bonjour, S.; Hunter, P.R.; Fewtrell, L.; Curtis, V. Hygiene and health: systematic review of handwashing practices worldwide and update of health effects. Tropical Medicine and International Health (2014) : [DOI: 10.1111/tmi.12339]