Quantifiable public health benefits associated with drinking water disinfection in western Kenya

Waterborne diseases are a leading cause of death worldwide, especially among children less than 5 years of age. Presently, there are few large epidemiological studies in east Africa quantifying the risk reduction in human illness from providing access to treated drinking water. To address this need, we examined the frequency of various illnesses in households with and without access to treated water. Using a 14-day retrospective cohort study design we ascertained health status information and household beliefs pertaining to water treatment from households in Kenya's Great Rift Valley. Logistic regression models were constructed to estimate human health benefits related to treated water access. Using a survey administered orally in Swahili and Kalenjin we obtained health and exposure data from 159 households representing 846 individuals in January 2013. Treated water was the primary source for 356 (42%) of the people studied. Multivariable logistic regression (adjusting for age, gender, and belief in water treatment) demonstrated decreased odds of vomiting (odds ratio = 0.40; 95% confidence interval (CI): 0.19 – 0.85), sore throat (OR = 0.55; CI 0.31 – 0.98), nausea (OR = 0.40; CI = 0.17 – 0.94), and fever (OR = 0.47; CI = 0.22 – 0.98) among those drinking treated water compared to those drinking untreated water. This analysis provides quantifiable evidence of the health benefits provided by drinking water treatment in Kenya's Great Rift Valley. Future analyses using our collected microbiological data are planned.