Esophageal cancer mortality and total hardness levels in Taiwan's drinkingwater

The possible association between the risk of esophageal cancer and hardness levels in drinking water from municipal supplies was investigated in a mat ched case-control study in Taiwan. All eligible esophageal cancer deaths (2 084 cases) of Taiwan residents from 1987 through 1996 were compared with de aths from other causes (2084 controls), and the hardness levels of the drin king water used by these residents were determined. Data on water hardness throughout Taiwan have been collected from the Taiwan Water Supply Corporat ion (TWSC). The control group consisted of people who died from other cause s and the controls were pair-matched to the cases by sex, year of birth, an d year of death. The results show that there is a 42% excess risk of mortal ity from esophageal cancer in relation to the use of soft water (adjusted o dds ratio and 95% confidence intervals was 1.42 (1.22-1.66). This is an imp ortant finding for the Taiwan water industry and human health. (C) 1999 Aca demic Press.