Trihalomethanes in Drinking Water and Bladder Cancer Burden in the European Union
Iro Evlampidou, Laia Font-Ribera, David Rojas‐Rueda, Esther Gràcia‐Lavedan, Nathalie Costet, Neil Pearce, Paolo Vineis, Jouni J. K. Jaakkola, Francis Delloye, Konstantinos C. Makris, Euripides G. Stephanou, Sophia Kargaki, František Kožíšek, Torben Sigsgaard, Birgitte Hansen, Jörg Schullehner, Ramon Nahkur, C. Galey, Christian Zwiener, Márta Vargha, Elena Righi, Gabriella Aggazzotti, Gunda Kalnina, Regina Gražulevičienė, Kinga Polańska, Dasa Gubkova, Katarina Bitenc, Emma H. Goslan, Manolis Kogevinas, Cristina M. Villanueva
Abstract
BACKGROUND: Trihalomethanes (THMs) are widespread disinfection by-products (DBPs) in drinking water, and long-term exposure has been consistently associated with increased bladder cancer risk. OBJECTIVE: We assessed THM levels in drinking water in the European Union as a marker of DBP exposure and estimated the attributable burden of bladder cancer. METHODS: We collected recent annual mean THM levels in municipal drinking water in 28 European countries (EU28) from routine monitoring records. We estimated a linear exposure-response function for average residential THM levels and bladder cancer by pooling data from studies included in the largest international pooled analysis published to date in order to estimate odds ratios (ORs) for bladder cancer associated with the mean THM level in each country (relative to no exposure), population-attributable fraction (PAF), and number of attributable bladder cancer cases in different scenarios using incidence rates and population from the Global Burden of Disease study of 2016. RESULTS: [standard deviation (SD) of 11.2]. The estimated bladder cancer PAF was 4.9% [95% confidence interval (CI): 2.5, 7.1] overall (range: 0-23%), accounting for 6,561 (95% CI: 3,389, 9,537) bladder cancer cases per year. Denmark and the Netherlands had the lowest PAF (0.0% each), while Cyprus (23.2%), Malta (17.9%), and Ireland (17.2%) had the highest among EU26. In the scenario where no country would exceed the current EU mean, 2,868 (95% CI: 1,522, 4,060; 43%) annual attributable bladder cancer cases could potentially be avoided. DISCUSSION: Efforts have been made to reduce THM levels in the European Union. However, assuming a causal association, current levels in certain countries still could lead to a considerable burden of bladder cancer that could potentially be avoided by optimizing water treatment, disinfection, and distribution practices, among other possible measures. https://doi.org/10.1289/EHP4495.