| A Randomized, Blinded, Controlled Trial Investigating the Gastrointestinal Health Effects of Drinking Water Quality Margaret E. Hellard, Martha I. Sinclair, Andrew B. Forbes, and Christopher K. Fairley Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia Abstract
A double-blinded, randomized, controlled trial was carried out in in Melbourne, Australia, to determine the contribution of drinking water to gastroenteritis. Melbourne is one of the few major cities in the world that draws drinking water from a protected forest catchment with minimal water treatment (chlorination only) . Six hundred families were randomly allocated to receive either real or sham water treatment units (WTUs) installed in their kitchen. Real units were designed to remove viruses, bacteria, and protozoa. Study participants completed a weekly health diary reporting gastrointestinal symptoms during the 68-week observation period. There were 2,669 cases of highly credible gastroenteritis (HCG) during the study (0.80 cases/person/year) . The ratio of HCG episode rates for the real WTU group compared to the sham WTU group was 0.99 (95% confidence interval, 0.85-1.15, p = 0.85) . We collected 795 fecal specimens from participants with gastroenteritis, and pathogens were not more significantly common in the sham WTU group. We found no evidence of waterborne disease in Melbourne. The application of this methodology to other water supplies will provide a better understanding of the relationship between human health and water quality. Key words: double-blind randomized trails, drinking water quality, gastroenteritis, waterborne disease. Environ Health Perspect 109:773-778 (2001) . [Online 1 August 2001] http://ehpnet1.niehs.nih.gov/docs/2001/109p773-778hellard/ abstract.html Address correspondence to M. Sinclair, E & P Medicine, Monash University Medical School, Alfred Hospital, Prahran, VIC 3181, Australia. Telephone: + 61 3 9903 0571. Fax: + 61 3 9903 0576. E-mail: martha.sinclair@med.monash.edu.au We extend special thanks to the Water Quality Study team (J. Ferguson, K. Gibson, I. Guise, H. Kazda, P. Lightbody, F. Savio, and G. Simmons) for their excellent work. We thank the Centers for Disease Control and Prevention (Atlanta, GA, USA) , the Communicable Disease Surveillance Centre (London, UK) , and P. Payment (University of Quebec, Montreal, Quebec, Canada) for access to their gastroenteritis questionnaires. This study was supported by the Cooperative Research Centre for Water Quality and Treatment, the Water Services Association of Australia, the Victorian Department of Human Services, Melbourne Water Corporation, South East Water Limited, Yarra Valley Water Limited, and City West Water Limited. Received 4 October 2000 ; accepted 5 February 2001.
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