Mortality among population with exposure to industrial air pollution containing nickel and other toxic metals.

OBJECTIVE

To assess disease mortality among people with exposure to metal-rich particulate air pollution.

METHODS

We conducted a cohort study on mortality from 1981 to 2005 among 33,573 people living near a nickel/copper smelter in Harjavalta, Finland. Nickel concentration in soil humus was selected as an indicator for long-term exposure. Relative risks--adjusted for age, socioeconomic status, and calendar period--were calculated for three exposure zones.

RESULTS

The relative risks for diseases of the circulatory system by increasing exposure were 0.93 (95% confidence interval = 0.79 to 1.09), 1.20 (1.04 to 1.39), and 1.18 (1.00 to 1.39) among men and 1.01 (0.88 to 1.17), 1.20 (1.04 to 1.38), and 1.14 (0.97 to 1.33) among women. Exclusion of smelter workers from the cohort did not materially change the results.

CONCLUSIONS

Long-term environmental exposure to metal-rich air pollution was associated with increased mortality from circulatory diseases.