Is there an association between ambient air pollution and bladder cancer incidence – Analysis of 15 European cohorts?

Background Ambient air pollution contains low concentrations of carcinogens implicated in the etiology of urinary bladder cancer. Little is known about whether exposure to air pollution influences bladder cancer in the general population. Objective We aimed to evaluate the association between long-term exposure to ambient air pollution and bladder cancer incidence. Design, setting and participants We obtained data from 15 population-based cohorts enrolled between 1985 and 2005 in eight European countries (N=303,431; mean follow-up 14.1 years). We estimated exposure to nitrogen oxides (NO2 and NOX), particulate matter (PM) with diameter Outcome measurements and statistical analysis We used Cox proportional-hazards models with adjustment for potential confounders for cohort-specific analyses and meta-analyses to estimate summary hazard ratios (HRs) for bladder cancer incidence. Results and Limitations During follow-up, 943 incident bladder cancer cases were diagnosed. In the meta-analysis, none of the exposures were associated with bladder cancer risk. The summary HRs associated with a 10-μg/m3 increase in NO2 and 5-μg/m3 increase in PM2.5 were 0.98 (95% confidence interval (CI): 0.89, 1.08) and 0.86 (95%CI: 0.63, 1.18), respectively. Limitations include lack of information about lifetime exposure. Conclusion There was no evidence of an association between exposure to outdoor air pollution levels at residence and risk of bladder cancer. Patient summary We assessed the link between outdoor air pollution at residence and bladder cancer, using the largest study population to date, extensive assessment of exposure and comprehensive data on personal risk factors such as smoking. We found no association between the levels of outdoor air pollution at residence and bladder cancer risk.1