Impact of zinc supplementation on diarrhoeal morbidity in rural children of West Bengal, India DN Gupta, SK Mondal, S Ghosh, K Rajendran, D Sur and B Manna National Institute of Cholera and Enteric Diseases, Calcutta, India Gupta DN, Mondal SK, Ghosh S, Rajendran K, Sur D and Manna B. Impact of zinc supplementation on diarrhoeal morbidity in rural children of West Bengal, India. Acta Pædiatr 2003; 92: 531–536. Stockholm. ISSN 0803-5253 Aim: To determine the role of zinc supplementation in reducing diarrhoeal morbidity in children. Methods: A randomized, double-blind, community-based intervention study was conducted in 280 rural children aged between 6 and 41 mo. Children were randomly allocated into three groups. One group received a daily dose of 10 mg zinc for 5 d wk 1 , another group received 50 mg zinc once weekly and the remaining group received placebo. Zinc was supplemented for 16 wk from November 1999. Diarrhoeal episodes were detected by weekly surveillance during the supplemen- tation period. Results: Eighty diarrhoeal episodes were detected among 59 children in all 3 groups. The groups were compared with each other at baseline and as regard to the outcome variable (incidence of diarrhoea). The proportion of children suffering from diarrhoea during the period was significantly lower in the zinc-supplemented groups (15.8% in daily and 16.5% in weekly group) than in the placebo group (30.8%). The incidence of diarrhoea in the daily and weekly zinc-supplemented groups was 0.68 and 0.69 episodes child 1 y 1 , and that in the placebo group was 1.67 episodes child 1 y 1 (relative risk 0.41, 95% confidence interval 0.24–0.71). Diarrhoeal incidence of <4 d duration was found to occur significantly less often in the supplemented groups. There was no difference in diarrhoeal incidence between the daily and weekly zinc-supplemented children. There were no detected adverse reactions in any of the supplemented groups. Conclusion: The study indicates that zinc supplementation is effective in reducing diarrhoeal morbidity when administered either daily or in a weekly schedule. Key words: Children, diarrhoea, double blind, zinc DN Gupta, National Institute of Cholera and Enteric Diseases, P-33, CIT Road, Scheme-XM, Beliaghata, Calcutta, India (Tel. 91 33 350 5533/4478/0448, fax. 91 33 350 5066, e-mail. dngupta31@yahoo.co.in) Malnutrition and diarrhoeal disease remain major public health problems, particularly in developing countries (1–5). Repeated attacks of diarrhoea are commonly associated with malnutrition, leading to further malnutrition, and resulting in a vicious cycle (6–7). Macronutrient deficiency is the main cause of malnutrition, but almost all malnourished children also suffer from micronutrient deficiency (8). Zinc is one of the most important micronutrients, deficiency of which leads to reduce immune function and increased morbid- ity from infectious diseases, including diarrhoea (9–10). A correlation between zinc deficiency and causation of diarrhoea has recently been documented in human subjects (11–14). Several community-based studies of zinc supplementation in children have also documented a substantial reduction in diarrhoeal incidence (15–17). In those studies zinc was supplemented daily, but daily supplementation may not be feasible. Weekly supple- mentation of zinc may have operational advantages over daily supplementation for mass distribution in future programmes. Therefore, a double-blind, placebo- controlled study was carried with two dosing schedules, daily and weekly dose, of zinc supplementation to determine the efficacy in reducing diarrhoeal morbidity among children below 4 y of age in the rural community in West Bengal, India. Patients and methods Study design A community-based, placebo-controlled, double-blind, randomized intervention study was undertaken to assess the impact of daily versus weekly supplementation of zinc on diarrhoeal morbidity. The project proposal was reviewed and approved by the institutional ethics committee. Study area and population The study was conducted in three adjoining villages  2003 Taylor & Francis. ISSN 0803-5253 Acta Pñdiatr 92: 531±536. 2003 DOI 10.1080/08035250310002722