A Case-Control Study of Diarrhea, Water and Sanitation in Rural Malawi

An epidemiologic case-control study was conducted to test 1) the hypothesis that improved water and sanitation would reduce diarrheal incidence in children under five years of age, and 2) the feasibility of using a case-control design to evaluate health impacts of environmental interventions. Both improved water sources and access to latrines were associated with increased rather than decreased diarrhea incidence except when the children were exclusively breastfed. This increased incidence may be the result of diminishing or delayed immunity to diarrheal diseases when sanitation and water facilities are improved. The results show the need for health interventions which couple improved environmental services and food hygiene. The significance of the findings are limited due to the poor precision of the estimates of the effect measures. Strong interactions between water, sanitation and breastfeeding would necessitate a sample size at least four times larger than what was used. Future case-control studies on diarrheal morbidity should anticipate such interactions and increase sample sizes to detect changes in diarrheal incidence which would be of public health significance.Master of Science in Public Healt