Long-term impact of arsenic in drinking water on bladder cancer health care and mortality rates 20 years after end of exposure.

PURPOSE

In this study we assessed bladder cancer health care and mortality trends in recent decades in a well studied arsenic exposed area in Northern Chile.

MATERIALS AND METHODS

Arsenic levels in the affected region were obtained for the last 60 years, and correlated with bladder cancer hospital discharge and mortality rates in recent decades.

RESULTS

Bladder cancer hospital discharge rates were significantly higher in the affected region (peak RR 3.6, 95% CI 3.0-4.7). Mortality rates for bladder cancer showed a trend of increase during the period analyzed, reaching peak mortality rates of 28.4 per 100,000 for men and 18.7 per 100,000 for women in the last 10 years. Poisson regression models showed an increased mortality risk in the studied region compared to the rest of the country until the present for men (IRR 5.3, 95% CI 4.8-5.8) and women (IRR 7.8, 95% CI 7.0-8.7). Mean age at cancer specific death was significantly lower in the exposed region (69.6 years, 95% CI 68.4-70.7 vs 73.7 years, 95% CI 73.3-74.2, p <0.01).

CONCLUSIONS

Exposure to arsenic is related to a significant need for bladder cancer health care and to high mortality rates even 20 years after having controlled arsenic levels in drinking water. Affected individuals should be aware of the significant impact of this ecological factor. Further research is required to identify strategies for the management of bladder cancer in arsenic exposed populations.