In Older Adults, Home Water Filtration Device Reduces Gastrointestinal Illness

Researchers found a 12% decrease in self-reported gastrointestinal illness per year among Sonoma County study participants using an active water filter. (Photo from Google Maps)

The first randomized controlled trial of household drinking water treatment in the homes of older adults found that a countertop water filter reduced the risk of gastrointestinal illness.

In the blinded intervention trial, researchers enrolled 988 participants age 55 or older in Sonoma, California.  Participants were randomly divided into two groups—half received an active water treatment device that included 1-μm filtration and ultraviolet treatment, while half received an identical looking sham device. Midway through the study, the devices were switched within the household to the opposite device type.

Following two, 26-week cycles, scientists found a 12% decrease in self-reported gastrointestinal illness per year among participants using the active versus sham water filter.1

The study, published in the November 2009 issue of the American Journal of Public Health, was led by COEH member John Colford Jr., a professor of epidemiology at UC Berkeley.  The five-year project cost $2.8 million and was funded by the National Institutes of Health.

Colford noted that the findings could be meaningful because the elderly may be less tolerant of gastrointestinal infections and be more susceptible to serious complications when infected. He noted that the study site was chosen because Sonoma drinking water met all federal standards for drinking water quality. He expects that the results will be included as one element in the current national discussions about how drinking water standards should be set for the elderly, for children, and for those with immunocompromising conditions (such as cancer or HIV). 


1 Colford JM Jr., Hilton JF, Wright CC, Arnold BF, Saha S S, Wade TJ, Schott J, Eisenberg JN. The Sonoma Water Evaluation Trial: A Randomized Drinking Water Intervention Trial to Reduce Gastrointestinal Illness in Older Adults. Am J Public Health. 2009 Nov;99(11):1988-95.

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