ASSOCIATIONS OF WATER, SANITATION, AND HYGIENE WITH TYPHOID FEVER IN CASE-CONTROL STUDIES: A SYSTEMATIC REVIEW AND META- ANALYSIS

Abstract

Intro: Typhoid fever is a major public health issue in low- and middle-income countries. It is transmitted through fecally contaminated food or water and thus improving water, sanitation, and hygiene (WASH) is considered key to its control. We sought to quantify the association between WASH and typhoid fever. Methods: We updated a previous review by including new findings from the literature indexed in Web of Science, Embase, and PubMed. We kept the search terms, typhoid and case-control, consistent with the previous review. We assessed the risk of bias using the Risk of Bias in Non-Randomized Studies of Interventions (ROBINS-I). We categorized WASH exposures according to the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene (JMP) classification. We conducted a Bayesian random-effects meta- analysis of odds ratios (ORs) extracted from the studies without a critical risk of bias. Findings: We identified 25 eligible articles including 19 articles from the previous review. Pooled ORs indicated limited hygiene (OR = 2.26, 95% CrI: 1.38 to 3.64), untreated water (OR = 2.21, 95% CrI: 1.53 to 3.48) and using surface water (OR = 2.16, 95% CrI: 1.24 to 3.60) increased odds of culture-confirmed typhoid fever. On the other hand, basic hygiene (OR = 0.6, 95% CrI: 0.38 to 0.97) and treated water (OR = 0.62, 95% CrI: 0.41 to 0.89) reduced odds of culture-confirmed typhoid fever. Conclusion: Our analyses updated quantitative evidence of association between WASH and typhoid fever. Our study findings will be useful to infer actionable insights on the most effective ways to control typhoid fever in low- and middle-income countries. Our analyses also offer a possibility to leverage JMP WASH data to explore potential burden of typhoid fever.