Water disinfection by-products and bladder cancer: is there a European specificity? A pooled and meta-analysis of European case–control studies

Abstract

Several epidemiological studies suggested an association between the risk of bladder cancer and the exposure to trihalomethanes (THMs), the main disinfection by-products (DBPs) of chlorinated water. A previous pooled analysis of case-control studies from North America and Europe estimated a summarized dose-response relation. For policy guidance of drinking water disinfection in Europe and because major differences exist in water disinfection practices and DBPs occurrence between both continents, specific risk estimates for bladder cancer in relation to DBPs exposure for European populations were needed. We conducted a pooled and a two-stage random-effect meta-analyses of three European case-control studies from France, Finland, and Spain (5467 individuals: 2381 cases and 3086 controls). Individual exposure to THMs was calculated combining information on residential history, estimates of the average total THMs (TTHM) level in tap water at the successive residences and personal water consumption. A significant odds-ratio was observed for men exposed to an average residential TTHM level > 50 μg/l (OR = 1.47 (1.05; 2.05)) when compared to men exposed to levels ≤ 5 μg/l. The linear trend of the exposure-risk association was significant (p = 0.01). Risks increased significantly for exposure levels above 25 μg/l and with more than 30 years of exposure to chlorinated water, but were mainly driven by the level rather than the duration of exposure. No significant association was found among women or with cumulative exposure through ingestion. There was no evidence of a differential exposure-response relation for TTHM and bladder cancer in Europe and North America. Consequently, a global exposure-risk relation based on 4351 cases and 7055 controls is now available.

Chlorine for Water Disinfection: Properties, Applications and Health Effects

“…The high exposure to THMs induces the occurrence of cancer, mainly bladder cancer and reproductive outcomes, especially small for gestational age intrauterine growth retardation (Nieuwenhuijsen et al 2000, Villanueva et al 2004Tardiff et al 2006;Grellier et al 2010;Costet et al 2011). The risks of cancer through ingestion of THMs were highest, followed by inhalation and dermal contact pathways.…”

Environmental Epigenomics: Applications of Epigenetic Biomarkers to Investigate Epigenetic Alterations from Environmental Exposures

“…Trihalomethanes (THMs) are the most prevalent group of DBPs and are used as surrogate estimates of overall exposure in epidemiologic studies. Lifetime exposure to THMs in drinking water but also through showering and swimming pools has been associated with bladder cancer (Costet et al 2011 ;Villanueva et al 2007 ). The carcinogenicity of DBPs is attributed to genotoxic and non-genotoxic mechanisms.…”

Health impact of disinfection by-products in swimming pools

“…Epidemiologic evidence indicates that exposure to THM, the most concentrated DBP, relates to an increased risk of bladder cancer [93,94]. Only one study have assessed specifically this exposure through swimming pools and found increased bladder cancer risk among subjects who had attended swimming pools [95].…”