The objective of this study was to evaluate whether exposure to disinfection by-products (DBP) is associated with
colon cancer. A matched case-control study was used to investigate the relationship between the risk of death attributed to
colon cancer and exposure to total
trihalomethanes (TTHM) in
drinking water in 65 municipalities in Taiwan. All
colon cancer deaths of the 65 municipalities from 1997 through 2006 were obtained from the Bureau of Vital Statistics of the Taiwan Provincial Department of Health. Controls were deaths from other causes and were pair-matched to the
cancer cases by gender, year of birth, and year of death. Each matched control was selected randomly from the set of possible controls for each
cancer case. Data on TTHM levels in
drinking water in study municipalities were collected from the Taiwan Environmental Protection Administration. The municipality of residence for
cancer cases and controls was assumed to be the source of the subject's TTHM exposure via
drinking water. The adjusted odds ratios (OR) for
colon cancer death for those with high TTHM levels in their
drinking water were 1.02 (0.87-1.2) and 1.04 (0.89-1.21) compared to the lowest group. The results of the present study show that there was no statistically significant association between TTHM in
drinking water at levels in this study and risk of death from
colon cancer.