Effects of Water Provision and Hydration on Cognitive Function among Primary-School Pupils in Zambia: A Randomized Trial

• Type of Material: Article
• Authors: Victoria Trinies, Emory University; Anna N. Chard, Emory University; Tommy Mateo, Schools Promoting Learning Achievement through Sanitation and Hygiene (SPLASH); Matthew Freeman, Emory University
• Language: English
• Date: 2016-03-07
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2016 Trinies et al
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pone.0150071
• Title of Journal or Parent Work: PLoS ONE
• ISSN: 1932-6203
• Volume: 11
• Issue: 3
• Start Page: e0150071
• End Page: e0150071
• Grant/Funding Information: This study was made possible by the generous support of the United States Agency for International Development (USAID) through its WASHplus (global) and SPLASH/Zambia projects.
• Keywords: Dehydration (medicine); Environmental Health; Attention; Recall (memory); Vision; Memory; Urine; Schools; Water resources
• Research Categories: Health Sciences, Public Health; Psychology, Cognitive

Abstract

There is a well-established link between hydration and improved cognitive performance among adults, with evidence of similar findings among children. No trials have investigated the impact of water provision on cognitive performance among schoolchildren in hot and arid low-resource settings. We conducted a randomized-controlled trial in five schools with limited water access in Chipata district in Eastern province, Zambia, to assess the efficacy of water provision on cognition. Pupils in grades 3–6 were randomly assigned to either receive a bottle of drinking water that they could refill throughout the day (water group, n = 149) or only have access to drinking water that was normally available at the school (control group, n = 143). Hydration was assessed in the morning before provision of water and in the afternoon through urine specific gravity (Usg) measured with a portable refractometer. In the afternoon we administered six cognitive tests to assess short-term memory, concentration, visual attention, and visual motor skills. Morning prevalence of dehydration, defined as Usg≥1.020, was 42%. Afternoon dehydration increased to 67% among the control arm and dropped to 10% among the intervention arm. We did not find that provision of water or hydration impacted cognitive test scores, although there were suggestive relationships between both water provision and hydration and increased scores on tests measuring visual attention. We identified key improvements to the study design that are warranted to further investigate this relationship.