The association of drinking water source and chlorination by-products with cancer incidence among postmenopausal women in Iowa: A prospective cohort study

Timothy J. Doyle, Wei Zheng, James R. Cerhan, Ching Ping Hong, Thomas A. Sellers, Lawrence H. Kushi, Aaron R. Folsam

Research output: Contribution to journalArticle

104 Scopus citations


Objectives: This study assessed the association of drinking water source and chlorination by-product exposure with cancer incidence. Methods: A cohort of 28 237 Iowa women reported their drinking water source. Exposure to chlorination by-products was determined from statewide water quality data. Results: In comparison with women who sed municipal groundwater sources, women with municipal surface water sources were at an increased risk of colon cancer and all cancers combined. A clear dose-response relation was observed between four categories of increasing chloroform levels in finished drinking water and the risk of colon cancer and all cancers combined. The relative risks were 1.00, 1.06, 1.39, and 1.68 for colon cancer and 1.00, 1.04, 1.24, and 1.25 for total cancers. No consistent association with either water source or chloroform concentration was observed for other cancer sites. Conclusions: These results suggest that exposure to chlorination by-products in drinking water is associated with increased risk of colon cancer.

Original languageEnglish (US)
Pages (from-to)1168-1176
Number of pages9
JournalAmerican journal of public health
Issue number7
StatePublished - Jul 1997


ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health

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