A Randomized, Controlled Trial of In-Home Drinking Water Intervention to Reduce Gastrointestinal Illness

Abstract

Trials have provided conflicting estimates of the risk of gastrointestinal illness attributable to tap water. To estimate this risk in an Iowa community with a well-run water utility with microbiologically challenged source water, the authors of this 2000-2002 study randomly assigned blinded volunteers to use externally identical devices (active device: 227 households with 646 persons; sham device: 229 households with 650 persons) for 6 months (cycle A). Each group then switched to the opposite device for 6 months (cycle B). The active device contained a 1-microm absolute ceramic filter and used ultraviolet light. Episodes of "highly credible gastrointestinal illness," a published measure of diarrhea, nausea, vomiting, and abdominal cramps, were recorded. Water usage was recorded with personal diaries and an electronic totalizer. The numbers of episodes in cycle A among the active and sham device groups were 707 and 672, respectively; in cycle B, the numbers of episodes were 516 and 476, respectively. In a log-linear generalized estimating equations model using intention-to-treat analysis, the relative rate of highly credible gastrointestinal illness (sham vs. active) for the entire trial was 0.98 (95% confidence interval: 0.86, 1.10). No reduction in gastrointestinal illness was detected after in-home use of a device designed to be highly effective in removing microorganisms from water.

Sodium Dichloroisocyanurate Tablets for Routine Treatment of Household Drinking Water in Periurban Ghana: A Randomized Controlled Trial

“…[2][3][4][5] Two double-blinded, placebo-controlled trials of nonchlorine based point-of-use water treatment interventions have been published in peer-reviewed literature, and neither found an impact on health. 27,35 Both took place in the United States and evaluated active and sham water filtration devices in households relying on water that met federal and state drinking water standards and requirements. 27,35 These studies Figure 3.…”

“…27,35 Both took place in the United States and evaluated active and sham water filtration devices in households relying on water that met federal and state drinking water standards and requirements. 27,35 These studies Figure 3. Percent of intervention and control households with ≥ 0.2 g/mL of free chlorine in stored water, by surveillance visit ( N = 240).…”

Quantification of Human Norovirus GII on Hands of Mothers with Children Under the Age of Five Years in Bagamoyo, Tanzania

“…HCGI was defined as having three or more loose, watery stools within a 24-hour period, blood in the stool, and/or vomiting using a 2-day recall period. 19,20 The remaining eligible households comprised of 51 spatially coherent household clusters with a mean cluster size of 10 households. A random number was then assigned to each household and sorted in ascending order, first by the random number and then by cluster number.…”

Detection of Coliforms in Drinking Water and its Effect on Human Health - A Review

“…One prospective intervention study found that consumers of reverse-osmosis (POU) filtered water had 20-35 % less gastrointestinal illnesses than those consuming regular tap water, with an excess of 14% of illness due to contaminants introduced in the distribution system (Payment 1991(Payment , 1997. Two other studies using randomized, blinded, controlled trials determined that the risks were equal among groups supplied with POU-treated water compared to untreated tap water (Hellard et al, 2001;Colford et al, 2005).…”