Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013 Aug 15;178(4):652-60.
doi: 10.1093/aje/kwt009. Epub 2013 May 5.

Biological and statistical approaches for modeling exposure to specific trihalomethanes and bladder cancer risk

Lucas A Salas  1 , Kenneth P Cantor, Adonina Tardon, Consol Serra, Alfredo Carrato, Reina Garcia-Closas, Nathaniel Rothman, Núria Malats, Debra Silverman, Manolis Kogevinas, Cristina M Villanueva
Affiliations

Biological and statistical approaches for modeling exposure to specific trihalomethanes and bladder cancer risk

Lucas A Salas et al. Am J Epidemiol. .

Abstract

Lifetime exposure to trihalomethanes (THM) has been associated with increased risk of bladder cancer. We explored methods of analyzing bladder cancer risk associated with 4 THM (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) as surrogates for disinfection by-product (DBP) mixtures in a case-control study in Spain (1998-2001). Lifetime average concentrations of THM in the households of 686 incident bladder cancer cases and 750 matched hospital-based controls were calculated. Several exposure metrics were modeled through conditional logistic regression, including the following analyses: total THM (μg/L), cytotoxicity-weighted sum of total THM (pmol/L), 4 THM in separate models, 4 THM in 1 model, chloroform and the sum of brominated THM in 1 model, and a principal-components analysis. THM composition, concentrations, and correlations varied between areas. The model for total THM was stable and showed increasing dose-response trends. Models for separate THM provided unstable estimates and inconsistent dose-response relationships. Risk estimation for specific THM is hampered by the varying composition of the mixture, correlation between species, and imprecision of historical estimates. Total THM (μg/L) provided a proxy measure of DBPs that yielded the strongest dose-response relationship with bladder cancer risk. A variety of metrics and statistical approaches should be used to evaluate this association in other settings.

Keywords: Spain; chloroform; complex mixtures; logistic models; principal-components analysis; trihalomethanes; urinary bladder neoplasms.

PubMed Disclaimer

References

    1. Nieuwenhuijsen MJ, Grellier J, Smith R, et al. The epidemiology and possible mechanisms of disinfection by-products in drinking water. Philos Transact A Math Phys Eng Sci. 2009;367(1904):4043–4076. - PubMed
    1. Krasner SW, Weinberg HS, Richardson SD, et al. Occurrence of a new generation of disinfection byproducts. Environ Sci Technol. 2006;40(23):7175–7185. - PubMed
    1. World Health Organization. Disinfectants and Disinfection By-Products. Geneva, Switzerland: World Health Organization; 2007. Water, Sanitation, and Health Programme, http://www.who.int/water_sanitation_health/dwq/S04.pdf. (Accessed October 31, 2012)
    1. King WD, Marrett LD. Case-control study of bladder cancer and chlorination by-products in treated water (Ontario, Canada) Cancer Causes Control. 1996;7(6):596–604. - PubMed
    1. King WD, Marrett LD, Woolcott CG. Case-control study of colon and rectal cancers and chlorination by-products in treated water. Cancer Epidemiol Biomarkers Prev. 2000;9(8):813–818. - PubMed

Publication types