Long-term air pollution exposure linked with bladder cancer risk in prospective UK Biobank analysis

In a prospective analysis of UK Biobank participants, long-term exposure to four ambient air pollutants was associated with increased bladder cancer risk, with the strongest reported association for fine particulate matter smaller than 2.5 micrometres (PM₂.₅). The findings are summarized in the study abstract and describe statistical associations rather than establishing that air pollution caused the cancers. The analysis included 469,105 participants who were free of bladder cancer at enrollment; 3,204 cases were identified during a median follow-up of 15.4 years.

Annual exposures to PM₂.₅, particulate matter smaller than 10 micrometres (PM₁₀), nitrogen dioxide (NO₂) and nitrogen oxides (NOx) were estimated using spatiotemporal models at a 1 km × 1 km resolution. Complete residential histories were used to derive time-weighted cumulative exposures. Time-dependent Cox models estimated hazard ratios while adjusting for demographic, socioeconomic and lifestyle factors. The investigators also constructed polygenic risk scores to assess genetic susceptibility and examined joint effects, interaction indices, population attributable fractions and modeled intervention scenarios.

All four pollutants showed statistically significant dose-response associations with bladder cancer risk. Long-term exposure to PM₂.₅ had the largest reported hazard ratio, 2.020 (95% confidence interval, 1.919–2.127), followed by PM₁₀ at 1.657 (1.580–1.738), NO₂ at 1.508 (1.441–1.578) and NOx at 1.450 (1.391–1.513). The elevated risk associated with air pollution was evident across all polygenic-risk-score strata. Participants with both high genetic risk and high exposure had the greatest joint hazard ratios: 8.75 for PM₂.₅, 6.32 for PM₁₀, 4.79 for NOx and 4.97 for NO₂. Additive interaction analyses indicated strong synergy, particularly for PM₂.₅ among high-risk individuals (P < 0.001).

The abstract reported population attributable fractions of 36.8% for annual average PM₂.₅ concentrations at or above the fourth-quartile level, 28.2% for PM₁₀, 24.8% for NOx and 24.7% for NO₂. In a theoretical intervention scenario, reaching World Health Organization guideline levels was projected to avert up to 80% of PM₂.₅-related cases; this was a model-based projection, not an observed policy effect. Because the available evidence describes an observational analysis based on modeled residential exposures, residual confounding and exposure misclassification remain possible, and the abstract does not present the study’s complete set of limitations.

Subject of Research: Associations between long-term ambient air pollution, genetic susceptibility and bladder cancer risk in the UK Biobank

Article Title: Air pollutants, genetic susceptibility, and bladder cancer risk: a prospective study

Article References: Liu, J., Tang, R., Wang, H., Luo, S., Wang, J., & Wu, P. (2026). Air pollutants, genetic susceptibility, and bladder cancer risk: a prospective study. BMC Cancer. https://doi.org/10.1186/s12885-026-17167-9

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17167-9

Keywords: air pollution, bladder cancer, UK Biobank, prospective cohort, PM₂.₅, PM₁₀, nitrogen dioxide, nitrogen oxides, polygenic risk, gene-environment interaction, pollutants, genetic