Chlorine is by far the most commonly used chemical for the disinfection of water supplies in North America. However, chlorine reacts with organic material in the raw water producing a number of halogenated hydrocarbon by-products. This population-based case-control study in Ontario, Canada examined the relationship between bladder cancer and exposure to chlorination by-products in public water supplies. Residence and water source histories and data from municipal water supplies were used to estimate individual exposure according to water source, chlorination status, and by-product levels (represented by trihalomethane [THM] concentration). Exposures were estimated for the 40-year period prior to the interview, using 696 cases diagnosed with bladder cancer between 1 September 1992 and 1 May 1994 and 1,545 controls with at least 30 years of exposure information. Odds ratios (OR) adjusted for potential confounders were used to estimate relative risk. Those exposed to chlorinated surface water for 35 or more years had an increased risk of bladder cancer compared with those exposed for less than 10 years (OR=1.41, 95 percent confidence interval [CI]=1.10–1.81). Those exposed to an estimated THM level≥50 μg/liter for 35 or more years had 1.63 times the risk of those exposed for less than 10 years (CI=1.08–2.46). These results indicate that the risk of bladder cancer increases with both duration and concentration of exposure to chlorination by-products, with population attributable risks of about 14 to 16 percent. Chlorination by-products represent a potentially important risk factor for bladder cancer.
Similar content being viewed by others
References
White, GC. Handbook of Chlorination. New York, NY (USA): Van Nostrand Reinhold, 1986: 256.
Federation of Associations on the Canadian Environment. National inventory of municipal waterworks and waste-water systems in Canada 1986. Ottawa, Ontario (Canada): Minister of Supply and Services Canada 1987.
Steven, AA, Moore, LA, Slocum, CJ, Smith, BL, Seeger, DR, Ireland, JC. By-products of water chlorination at ten operating utilities. In: Jolley, R, Condie, L, Johnson, JD, et al, eds. Water Chlorination: Chemistry, Environmental Impact and Health Effects. Chelsea, Michigan (USA): Lewis Publishers, Inc, 1990: 6:579–604.
International Agency for Research on Cancer. Chlorinated drinking-water; chlorination by-products; some other halogenated compounds; cobalt and cobalt compounds. Lyon, France: IARC, 1991; IARC Monogr Eval Carcinog Risk Hum, Vol. 52.
Cantor, KP. Epidemiologic studies and risk assessment of volatile organic compounds in drinking water. In: Ram, NM, Christman, RF, Cantor, KP, eds. Significance and Treatment of Volatile Organic Compounds in Water Supplies. Chelsea, MI (USA): Lewis Publishers, 1990: 465–84.
Bull, RJ, Robinson, M, Meier, JR, Stober, J. Use of biological assay systems to assess the relative carcinogenic hazards of disinfection by-products. Environ Health Perspect 1982; 46: 215–27.
McGeehin, MA, Reif, JS, Becher, JC, Mangione, EJ.Case-control study of bladder cancer and water disinfection methods in Colorado. Am J Epidemiol 1993; 138: 492–501.
Zierler, S, Feingold, L, Damley, RA, Craun, G. Bladder cancer in Massachusetts related to chlorinated and chloraminated drinking water: A case-control study. Arch Environ Health 1988; 43: 195–200.
Cantor, KP, Hoover, R, Hartge, P, et al. Bladder cancer, drinking water source and tap water consumption: a case-control study. JNCI 1987; 79: 1269–79.
Wilkins, JR, Comstock, GW. Source of drinking water at home and site specific cancer incidence in Washington County, Maryland. Am J Epidemiol 1981; 114: 178–90.
Gottlieb, MS, Carr, JK, Clarkson, JR. Drinking water and cancer incidence in Louisiana. Am J Epidemiol 1982; 116: 652–67.
Young, TB, Kanarek, MS, Tsiatis, AA. Epidemiologic study of drinking water chlorination and Wisconsin female cancer mortality. JNCI 1981; 67: 1991–98.
Brenniman, GR, Lagos, J, Amsel, J. Case-control study of cancer deaths in Illinois communities served by chlorinated and non-chlorinated water. In: Jolley, RL, Brings, W, Coamings, RB, eds. Water Chlorination Environmental Impact and Health Effects. Ann Arbor, MI (USA): Ann Arbor Science Publishers, 1980: 3: 1043–57.
Alavanja, M, Goldstein, I, Susser, M. A case-control study of gastrointestinal and urinary tract cancer mortality and drinking water chlorination. In: Jolley, RL, Brings, W, Coamings, RB, eds. Water Chlorination Environmental Impact and Health Effects. Ann Arbor, MI (USA): Ann Arbor Science Publishers, 1980: 3: 395–409.
Morris, RD, Audet, AM, Angelillo, IF, Chalmers, TC, Mosteller, F. Chlorination, chlorination by-products, and cancer: A meta-analysis. Am J Public Health 1992; 82: 955–63.
Lynch, CF, Woolson, RF, O'Gorman, T, Cantor, KP. Chlorinated drinking water and bladder cancer: effect of misclassification on risk estimates. Arch Environ Health 1989; 44: 252–9.
World Health Organization. International Classification of Diseases, Ninth Revision. Geneva, Switzerland: WHO, 1977.
Robles, SC, Marrett, LD, Clarke, EA, Risch, HA. An application of capture-recapture methods to the estimation of completeness of cancer registration. J Clin Epidemiol 1988; 41: 495–501.
Breslow, NE, Day, NE, eds. Statistical Methods in Cancer Research, Vol 1. The Analysis of Case-control Studies. Lyon, France: International Agency for Research on Cancer, 1980; IARC Sci. Pub. No. 32.
Bull, RJ, Meier, JR, Robinson, M, et al. Evaluation of mutagenic and carcinogenic properties of brominated and chlorinated acetonitriles, by-products of chlorination. Fundam Appl Toxicol 1985; 5: 1065–74.
Marrett, LD, Kreiger, N, Dodds, L, Hilditch, S. The effect on response rates of offering a small incentive with a mailed questionnaire. Ann Epidemiol 1992; 2: 745–53.
Siemiatycki, J, Dewar, R, Nadon, L, Gérin, M. Occupational risk factors for bladder cancer: Results from a case-control study in Montreal, Quebec, Canada. Am J Epidemiol 1994; 140: 1061–80.
Bruzzi, P, Green, SB, Byar, DP, et al. Estimating the population attributable risk for multiple risk factors using case-control data. Am J Epidemiol 1985; 122: 904–14.
Additional information
Dr King is with the Department of Community Health and Epidemiology, Queen's University, Kingston, Ontario, Canada. Dr Marrett is with the Ontario Cancer Treatment and Research Foundation and the Department of Preventive Medicine and Biostatistics, University of Toronto Canada. Address correspondence to Dr King, Department of Community Health and Epidemiology, Queen's University, Kingston, Ont., Canada, K7L 3N6. This research was funded by Health Canada and also was supported by the National Health Research and Development Program through a fellowship to W.D.K.
Rights and permissions
About this article
Cite this article
King, W.D., Marrett, L.D. Case-control study of bladder cancer and chlorination by-products in treated water (Ontario, Canada). Cancer Causes Control 7, 596–604 (1996). https://doi.org/10.1007/BF00051702
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00051702