Environmental health. Chlorinated drinking water and pancreatic cancer

Abstract

In order to examine the potential association between chlorinated drinking water and the incidence of pancreatic cancer, a population-based case-control study was performed on data obtained from the Turku area in Finland. The study base was approximately 220,000 persons. All 183 pancreatic cancer cases, diagnosed during 1989–1991, were included in the study. Each case had 2 randomly selected controls. The criterion for the exposure to chlorination by-products (CBPs) was that the subject had had chlorinated drinking water from a surface source available at home. Residential addresses with chlorinated or non-chlorinated water were obtained for up to the previous 20 years prior to diagnosis. The odds ratios (OR) varied between 0.20 and 0.66 depending on the length of the cumulative exposure time. This indicates that those exposed to chlorinated drinking water had a lower risk of contracting pancreatic cancer than the unexposed. The result is in gross agreement with earlier investigations which have mainly shown negative or inadequate associations. The side-effects of drinking water disinfection are unproven, because the published research results are inconsistent. The benefits of chlorination, however, are undeniable. Continuous water disinfection is needed in order to avoid waterborne epidemics and chlorination is the only available method in many countries.