Individual and Household Risk Factors for Symptomatic Cholera Infection: A Systematic Review and Meta-analysis

BACKGROUND: Cholera has caused 7 global pandemics, including the current one which has been ongoing since 1961. A systematic review of risk factors for symptomatic cholera infection has not been previously published. METHODS: In accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, we performed a systematic review and meta-analysis of individual and household risk factors for symptomatic cholera infection. RESULTS: We identified 110 studies eligible for inclusion in qualitative synthesis. Factors associated with symptomatic cholera that were eligible for meta-analysis included education less than secondary level (summary odds ratio [SOR], 2.64; 95% confidence interval [CI], 1.41–4.92; I(2) = 8%), unimproved water source (SOR, 3.48; 95% CI, 2.18–5.54; I(2) = 77%), open container water storage (SOR, 2.03; 95% CI, 1.09–3.76; I(2) = 62%), consumption of food outside the home (SOR, 2.76; 95% CI, 1.62–4.69; I(2) = 64%), household contact with cholera (SOR, 2.91; 95% CI, 1.62–5.25; I(2) = 89%), water treatment (SOR, 0.37; 95% CI, .21–.63; I(2) = 74%), and handwashing (SOR, 0.29; 95% CI, .20–.43; I(2) = 37%). Other notable associations with symptomatic infection included income/wealth, blood group, gastric acidity, infant breastfeeding status, and human immunodeficiency virus infection. CONCLUSIONS: We identified potential risk factors for symptomatic cholera infection including environmental characteristics, socioeconomic factors, and intrinsic patient factors. Ultimately, a combination of interventional approaches targeting various groups with risk-adapted intensities may prove to be the optimal strategy for cholera control.