Long-term exposure to ambient air pollution and cardiopulmonary mortality in women.

BACKGROUND: Living close to major roads or highways has been suggested to almost double the risk of dying from cardiopulmonary causes. We assessed whether long-term exposure to air pollution originating from motorized traffic and industrial sources is associated with total and cause-specific mortality in a cohort of women living in North Rhine-Westphalia, Germany.

METHODS: The study was a follow-up of a series of cross-sectional studies carried out during the 1980s and 1990s on the health of women (age 50-59 years). Approximately 4800 women were followed up for vital status and migration. Exposure to air pollution was defined by distance to major roads calculated from Geographic Information System data and by 1- and 5-year average nitrogen dioxide (NO2) and particle (PM10) concentrations calculated from air monitoring station data. We analyzed associations between exposure and mortality using Cox's proportional hazards models adjusting for confounders. Relative risks (RRs) refer to an interquartile range increase in exposure (16 microg/m for NO2; 7 microg/m for PM10).

RESULTS: During the follow-up period, 8% of the women died, 3% from cardiopulmonary causes. Cardiopulmonary mortality was associated with living within a 50-meter radius of a major road (adjusted RR = 1.70; 95% confidence interval = 1.02-2.81), with NO2 (1.57; 1.23-2.00 for 1-year average), and with PM10 (1.34; 1.06-1.71 for 1-year average). Exposure to NO2 was also associated with all-cause mortality (1.17; 1.02-1.34). No association was seen with noncardiopulmonary nonlung cancer mortality.

CONCLUSIONS: Living close to major roads and chronic exposure to NO2 and PM10 may be associated with an increased mortality due to cardiopulmonary causes.