Background: Evidence on the association between colorectal cancer and exposure to disinfection by-products in drinking water is inconsistent.
Objectives: We assessed long-term exposure to trihalomethanes (THMs), the most prevalent group of chlorination by-products, to evaluate the association with colorectal cancer.
Methods: A multicenter case–control study was conducted in Spain and Italy in 2008–2013. Hospital-based incident cases and population-based (Spain) and hospital-based (Italy) controls were interviewed to ascertain residential histories, type of water consumed in each residence, frequency and duration of showering/bathing, and major recognized risk factors for colorectal cancer. We estimated adjusted odds ratios (OR) for colorectal cancer in association with quartiles of estimated average lifetime THM concentrations in each participant’s residential tap water (micrograms/liter; from age 18 to 2 years before the interview) and estimated average lifetime THM ingestion from drinking residential tap water (micrograms/day).
Results: We analyzed 2,047 cases and 3,718 controls. Median values (ranges) for average lifetime residential tap water concentrations of total THMs, chloroform, and brominated THMs were 30 (0–174), 17 (0–63), and 9 (0–145) μg/L, respectively. Total THM concentration in residential tap water was not associated with colorectal cancer (OR = 0.92, 95% CI: 0.66, 1.28 for highest vs. lowest quartile), but chloroform concentrations were inversely associated (OR = 0.31, 95% CI: 0.24, 0.41 for highest vs. lowest quartile). Brominated THM concentrations showed a positive association among men in the highest versus the lowest quartile (OR = 1.43, 95% CI: 0.83, 2.46). Patterns of association were similar for estimated average THM ingestion through residential water consumption.
Conclusions: We did not find clear evidence of an association between detailed estimates of lifetime total THM exposure and colorectal cancer in our large case–control study population. Negative associations with chloroform concentrations and ingestion suggest differences among specific THMs, but these findings should be confirmed in other study populations.
1ISGlobal, Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain; 2IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain; 3Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain; 4CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain; 5Department of Epidemiology, IRCCS (Istituto di Ricerche Farmacologiche Mario Negri), Milan, Italy; 6Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy; 7Department of Preventive Medicine and Public Health, University of León, León, Spain; 8Cancer and Environmental Epidemiology Unit, National Centre for Epidemiology, Carlos III Institute of Health, Madrid, Spain; 9Cancer Epidemiology Research Group, Oncology and Hematology Area, IIS (Instituto de Investigación Sanitaria) Puerta De Hierro, Madrid, Spain; 10Department of Preventive Medicine and Public Health, University of Cantabria, Santander, Spain; 11IDIVAL (Instituto de Investigación Sanitaria Valdecilla), Santander, Spain; 12Centre for Research in Public Health, Valencia, Spain; 13Public Health Division of Gipuzkoa, Biodonostia Research Institute, San Sebastian, Spain; 14Instituto de Salud Pública y Laboral de Navarra, Pamplona, Spain; 15Oncology Institute IUOPA (Instituto Universitario de Oncología del Principado de Asturias), Universidad de Oviedo, Asturias, Spain; 16Department of Epidemiology, Murcia Regional Health Council, IMIB-Arrixaca (Biomedical Research Institute of Murcia), Murcia, Spain; 17Unit of Epidemiology and Biostatistics, CRO (Centro di Riferimento Oncologico) Aviano National Cancer Institute, IRCCS, Aviano, Italy; 18Institute of Hygiene and Clinical Epidemiology, University Hospital of Udine, Udine, Italy; 19Department of Biological and Medical Sciences, University of Udine, Udine, Italy; 20General Division of Public Health, Quality and Innovation, Ministry of Health, Social Services and Equity, Madrid, Spain; 21Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain; 22Department of Clinical Sciences, University of Barcelona, Barcelona, Spain; 23Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Milan, Italy
Recommended Citation:
Cristina M. Villanueva,1,2,et al. Colorectal Cancer and Long-Term Exposure to Trihalomethanes in Drinking Water: A Multicenter Case–Control Study in Spain and Italy[J]. Environmental Health Perspectives,2017-01-01,Volume 125(Issue 1):56