Long-term exposure to NO2 and PM10 and all-cause and cause-specific mortality in a prospective cohort of women

We assessed whether long-term exposure to air pollution is
associated with all-cause and cause-specific mortality during a
period of declining particulate matter concentrations.
Approximately 4800 women aged 55 years from North Rhine-Westphalia,
Germany, were followed for up to 18 years. Exposure to air
pollution was assessed in two ways: (1) using the distance between
the residential address and the nearest major road, as calculated
from Geographic Information System data and (2) calculating 1-year
average particulate matter concentrations below 10 mu m (PM10) and
nitrogen dioxide (NO2) levels using data from the nearest
air-monitoring station data to the subjects' residences. Ninety-two
per cent of all subjects lived in the same community during the
entire follow-up period. Associations between mortality and
exposure were assessed using Cox's proportional hazards models,
including confounder adjustment. Sixteen per cent of women passed
away during the follow-up period. An increase of 7 mu g/m(3) PM10
(IQR) was associated with an increased HR for all-cause (HR 1.15,
95% CI (1.04 to 1.27)), cardiopulmonary (HR 1.39, 95% CI (1.17 to
1.64)), and lung cancer mortality (HR 1.84, 95% CI (1.23 to 2.74)).
An increase of 16 mu g/m(3) (IQR) NO2 exposure was associated with
all-cause (HR 1.18, 95% CI (1.07 to 1.30)) and cardiopulmonary
mortality (HR 1.55, 95% CI (1.30 to 1.84)). The association between
cardiopulmonary mortality and PM10 was reduced for the extended
follow-up period, during which PM10 concentrations (but not NO2
concentrations) were lower. Living close to a major road was
associated with an increased relative risk for all-cause,
cardiopulmonary and respiratory mortality. These associations were
temporally stable. Long-term exposure to ambient PM10 and NO2 was
associated with increased mortality rates.