Apparent benefit of water filters may be an artifact of study design.
Hunter
Paul R
PR
D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D002140:California / Q000453:epidemiology; D018592:Cross-Over Studies; D005374:Filtration; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000517:prevention & control*; D006801:Humans; D015994:Incidence; D015995:Prevalence; D016032:Randomized Controlled Trials as Topic; D012107:Research Design; D012306:Risk; D018508:Water Purification / Q000379:methods*; D014881:Water Supply