Water-Related Exposures and Bladder Cancer Risk: A Comprehensive Epidemiologic Review.

Bladder cancer remains a prevalent malignancy worldwide, with increasing attention directed toward environmental determinants-particularly those related to water. This review examines the dual role of water, acting both as a vehicle for carcinogenic contaminants and as a protective factor through adequate hydration in the pathogenesis of bladder cancer. A comprehensive synthesis of epidemiologic studies was performed, focusing on major water-related exposures, including arsenic, disinfection by-products (DBP), nitrates, per- and polyfluoroalkyl substances (PFAS), and total fluid intake. The findings were evaluated in terms of the strength of association, biological plausibility, and public health relevance. Arsenic and DBPs have been consistently linked to an increased risk of bladder cancer, supported by robust evidence from case-control and cohort studies conducted across diverse geographic regions. In contrast, associations with nitrate and PFAS exposures remain less consistent and warrant further investigation. Conversely, higher water consumption seems to confer a protective effect, likely through dilution of urinary carcinogens and increased voiding frequency. Drinking-water quality and consumption behaviors represent modifiable determinants of bladder cancer risk. Regulatory measures targeting established contaminants, together with behavioral strategies promoting adequate hydration, could substantially contribute to prevention efforts. Continued research is essential to clarify the role of emerging exposures and to inform evidence-based global water safety policies.