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

• Published in: Occupational and environmental medicine (London, England) England), 2011-05, Vol.68 (5), p.379-385
• Main Authors: Costet, N, Villanueva, C M, Jaakkola, J J K, Kogevinas, M, Cantor, K P, King, W D, Lynch, C F, Nieuwenhuijsen, M J, Cordier, S
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Biological and medical sciences; Bladder; Bladder cancer; Byproducts; Cancer; Case studies; Case-Control Studies; Chlorination; Disinfection; disinfection by-products; Dose-Response Relationship, Drug; Drinking; Drinking water; Environmental Exposure; Environmental Exposure - adverse effects; Environmental Exposure - analysis; Epidemiology. Vaccinations; Estimates; Europe; Exposure; Female; General aspects; Humans; Infectious diseases; Ingestion; Life Sciences; Male; Medical sciences; Meta analysis; Middle Aged; Nephrology. Urinary tract diseases; Potable water; Review; Risk; Surface water; Tap water; Tobacco smoking; Trihalomethanes; Trihalomethanes - analysis; Trihalomethanes - toxicity; Tumors of the urinary system; Urinary bladder; Urinary Bladder Neoplasms; Urinary Bladder Neoplasms - chemically induced; Urinary Bladder Neoplasms - epidemiology; Urinary system involvement in other diseases. Miscellaneous; Urinary tract. Prostate gland; urological; Waste byproducts; water; Water consumption; Water Pollutants, Chemical; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity; Water Purification; Water Purification - methods; Water Supply; Water Supply - analysis
• ISSN: 1351-0711; 1470-7926
• DOI: 10.1136/oem.2010.062703

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.