Long-term ambient multipollutant exposures and mortality.
BACKGROUND
population-based studies have demonstrated associations between ambient air pollution exposures and mortality, but few have been able to adjust for occupational exposures. Additionally, two studies have observed higher risks in individuals with occupational dust, gas, or fume exposure.


OBJECTIVE
we examined the association of ambient residential exposure to particulate matter less than 10 microm in diameter (PM(10)), particulate matter less than 2.5 microm in diameter (PM(2.5)), NO(2), SO(2), and mortality in 53,814 men in the U.S. trucking industry.


METHODS
exposures for PM(10), NO(2), and SO(2) at each residential address were assigned using models combining spatial smoothing and geographic covariates. PM(2.5) exposures in 2000 were assigned from the nearest available monitor. Single and multipollutant Cox proportional hazard models were used to examine the association of an interquartile range (IQR) change (6 microg/m(3) for PM(10), 4 microg/m(3) for PM(2.5), 4ppb for SO(2), and 8ppb for NO(2)) and the risk of all-cause and cause-specific mortality.


RESULTS
an IQR change in ambient residential exposures to PM(10) was associated with a 4.3% (95% confidence interval [CI], 1.1-7.7%) increased risk of all-cause mortality. The increase for an IQR change in SO(2) was 6.9% (95% CI, 2.3-11.6%), for NO(2) was 8.2% (95% CI, 4.5-12.1%), and for PM(2.5) was 3.9% (95% CI, 1.0-6.9%). Elevated associations with cause-specific mortality (lung cancer, cardiovascular and respiratory disease) were observed for PM(2.5), SO(2), and NO(2), but not PM(10). None of the pollutants were confounded by occupational exposures. In multipollutant models, overall, the associations were attenuated, most strongly for PM(10). In sensitivity analyses excluding long-haul drivers, who spend days away from home, larger hazard ratios were observed.


CONCLUSIONS
in this population of men, residential ambient air pollution exposures were associated with mortality.
Hart
Jaime E
JE
Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA. jaime.hart@channing.harvard.edu
Garshick
Eric
E
Dockery
Douglas W
DW
Smith
Thomas J
TJ
Ryan
Louise
L
Laden
Francine
F
D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D002318:Cardiovascular Diseases / Q000139:chemically induced / Q000401:mortality*; D002423:Cause of Death / Q000639:trends; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009784:Occupational Diseases / Q000401:mortality*; D052638:Particulate Matter / Q000009:adverse effects*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D013997:Time Factors; D014481:United States / Q000453:epidemiology
D000395:Air Pollutants, Occupational; D052638:Particulate Matter