Drinking water quality and incidence of Diarrhoea in children aged 6 months to 15 years: Findings from a paediatric cohort in Vellore, Southern India

Abstract Introduction The coverage of access to basic drinking water and sanitation facilities in India was estimated to be 93% and 60%, respectively, in 2017. The monitoring of the burden of diarrhoeal illnesses, especially in children, remains important to assess the impact of the expansion of water and sanitation (WaSH) in the Indian setting. This study aimed to estimate the burden of diarrhoea in an established longitudinal pediatric cohort in an urban settlement of Vellore in South India. Methods The ‘Surveillance for Enteric Fever in India (SEFI)’ cohort established in an urban settlement of Vellore, south India, enrolled 6760 children aged between 6 months and 15 years. The cohort was followed up for typhoid and paratyphoid fever between 2017 and 2019. Field research assistants contacted caregivers of these children weekly to elicit any diarrhoeal illness in the child in the preceding week. As a part of SEFI environmental surveillance, drinking water samples from the study households were tested for coliforms. Sociodemographic characteristics, including source of drinking water, sanitation and hygiene practices, were collected. Incidence of diarrhoea was estimated and expressed as the number of diarrhoeal episodes over child-years of observation (CYO). Poisson regression analysis was performed to identify predictors of diarrhoeal episodes. Results The estimated incidence of diarrhoea in the 6501 children followed up between November 1, 2017, and October 31, 2019, was 31.1 episodes per 100 CYO, with children in the age group of 6 months and 10,000/100 mL. Only about one-third of the cohort (n=2293, 35.5%) lived in households with access to improved sanitation. Multivariable analysis showed that children aged