title: Colorectal Cancer and Long-Term Exposure to Trihalomethanes in Drinking Water: A Multicenter Case-Control Study in Spain and Italy.
abstract: Evidence on the association between colorectal cancer and exposure to disinfection by-products in drinking water is inconsistent.
  
  
  
  We assessed long-term exposure to trihalomethanes (THMs), the most prevalent group of chlorination by-products, to evaluate the association with colorectal cancer.
  
  
  
  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).
  
  
  
  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.
  
  
  
  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. Citation: Villanueva CM, Gracia-Lavedan E, Bosetti C, Righi E, Molina AJ, Martín V, Boldo E, Aragonés N, Perez-Gomez B, Pollan M, Gomez Acebo I, Altzibar JM, Jiménez Zabala A, Ardanaz E, Peiró R, Tardón A, Chirlaque MD, Tavani A, Polesel J, Serraino D, Pisa F, Castaño-Vinyals G, Espinosa A, Espejo-Herrera N, Palau M, Moreno V, La Vecchia C, Aggazzotti G, Nieuwenhuijsen MJ, Kogevinas M. 2017. Colorectal cancer and long-term exposure to trihalomethanes in drinking water: a multicenter case---control study in Spain and Italy. Environ Health Perspect 125:56-65; http://dx.doi.org/10.1289/EHP155.
authors.affiliation: ISGlobal, Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Villanueva
authors.forename: Esther
authors.initials: E
authors.lastname: Gracia-Lavedan
authors.forename: Cristina
authors.initials: C
authors.lastname: Bosetti
authors.forename: Elena
authors.initials: E
authors.lastname: Righi
authors.forename: Antonio José
authors.initials: AJ
authors.lastname: Molina
authors.forename: Vicente
authors.initials: V
authors.lastname: Martín
authors.forename: Elena
authors.initials: E
authors.lastname: Boldo
authors.forename: Nuria
authors.initials: N
authors.lastname: Aragonés
authors.forename: Beatriz
authors.initials: B
authors.lastname: Perez-Gomez
authors.forename: Marina
authors.initials: M
authors.lastname: Pollan
authors.forename: Ines Gomez
authors.initials: IG
authors.lastname: Acebo
authors.forename: Jone M
authors.initials: JM
authors.lastname: Altzibar
authors.forename: Ana Jiménez
authors.initials: AJ
authors.lastname: Zabala
authors.forename: Eva
authors.initials: E
authors.lastname: Ardanaz
authors.forename: Rosana
authors.initials: R
authors.lastname: Peiró
authors.forename: Adonina
authors.initials: A
authors.lastname: Tardón
authors.forename: Maria Dolores
authors.initials: MD
authors.lastname: Chirlaque
authors.forename: Alessandra
authors.initials: A
authors.lastname: Tavani
authors.forename: Jerry
authors.initials: J
authors.lastname: Polesel
authors.forename: Diego
authors.initials: D
authors.lastname: Serraino
authors.forename: Federica
authors.initials: F
authors.lastname: Pisa
authors.forename: Gemma
authors.initials: G
authors.lastname: Castaño-Vinyals
authors.forename: Ana
authors.initials: A
authors.lastname: Espinosa
authors.forename: Nadia
authors.initials: N
authors.lastname: Espejo-Herrera
authors.forename: Margarita
authors.initials: M
authors.lastname: Palau
authors.forename: Victor
authors.initials: V
authors.lastname: Moreno
authors.forename: Carlo
authors.initials: C
authors.lastname: La Vecchia
authors.forename: Gabriella
authors.initials: G
authors.lastname: Aggazzotti
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nieuwenhuijsen
authors.forename: Manolis
authors.initials: M
authors.lastname: Kogevinas
mesh_terms: D000328:Adult; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D060766:Drinking Water / Q000737:chemistry*; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006801:Humans; D007558:Italy; D013030:Spain / Q000453:epidemiology; D022882:Trihalomethanes / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods
chemical_list: D060766:Drinking Water; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical