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

IntroductionThe 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. MethodsThe 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. ResultsThe 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 <5 years having a higher incidence of diarrhoea than those aged between 5 and 15 years (58.6 versus 22 episodes per 100 CYO). Of the 6467 children with information on WaSH available, 5812 (89.9%) used the public distribution system for drinking water. Of the 1804 drinking water samples tested, 1346 (74.6%) had coliform counts >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 <2 years, residing in crowded settlements, using the public distribution system for drinking water and from households with poor hygiene practices related to excreta disposal of under-five children had a higher risk for diarrhoea. ConclusionApproximately 8 in 10 children in urban Vellore lack access to safely managed drinking water, and thereby, are at a high risk for diarrheal illnesses, especially in the under-5 children. With rapidly expanding urbanisation in the Indian setting, it is pertinent that emphasis be laid on robust planning and provision of safely managed water and sanitation.