Table 2.

Odds ratios per interquartile range (IQR) increase in particulate matter ${\mathrm{PM}}_{2.5}$ ($4.4{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$), ${\text{NO}}_2$ ($7.3\text{ppb}$), and ${\mathrm{PM}}_{10}$ ($5.8{\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$).

Exposure and outcome	Cases	Age adjusted		Fully adjusted
		OR (95% CI)	p-Value	OR (95% CI)	p-Value
${\mathrm{PM}}_{2.5}$
Incident chronic bronchitis	638	0.94 (0.84, 1.05)	0.256	0.94 (0.83, 1.06)	0.289
Prevalent (at baseline)
Chronic bronchitis	1,351	1.04 (0.97, 1.13)	0.276	1.04 (0.96, 1.13)	0.318
Chronic cough	3,749	1.03 (0.98, 1.08)	0.213	1.04 (0.99, 1.10)	0.103
Chronic phlegm	2,776	1.07 (1.02, 1.13)	0.010	1.04 (0.98, 1.10)	0.213
Chronic cough or phlegm	5,271	1.05 (1.01, 1.10)	0.015	1.04 (1.00, 1.09)	0.067
${\text{NO}}_2$
Incident chronic bronchitis	638	0.95 (0.87, 1.03)	0.198	1.00 (0.92, 1.09)	0.974
Prevalent (at baseline)
Chronic bronchitis	1,351	1.00 (0.95, 1.06)	0.923	1.05 (0.99, 1.11)	0.136
Chronic cough	3,749	1.02 (0.99, 1.06)	0.215	1.06 (1.02, 1.10)	0.002
Chronic phlegm	2,776	1.01 (0.97, 1.05)	0.730	1.02 (0.98, 1.07)	0.266
Chronic cough or phlegm	5,271	1.02 (0.99, 1.05)	0.199	1.04 (1.01, 1.08)	0.008
${\mathrm{PM}}_{10}$
Incident chronic bronchitis	638	0.92 (0.85, 1.01)	0.066	0.98 (0.90, 1.08)	0.745
Prevalent (at baseline)
Chronic bronchitis	1,351	1.06 (1.01, 1.12)	0.027	1.07 (1.01, 1.13)	0.019
Chronic cough	3,749	1.04 (1.00, 1.07)	0.045	1.04 (1.00, 1.08)	0.030
Chronic phlegm	2,776	1.07 (1.03, 1.12)	$<0.001$	1.07 (1.02, 1.11)	0.002
Chronic cough or phlegm	5,271	1.05 (1.01, 1.08)	0.001	1.05 (1.02, 1.08)	0.003

Note: Each outcome was compared to all participants without that outcome. The total number of participants with nonmissing data on all covariates was 38,006 for the analysis of incident outcomes, 44,158 for prevalent outcomes. Fully adjusted model includes age, race/ethnicity, body mass index, education, household income, occupational exposure to vapors/fumes or dust (ever), smoking status, total pack-years, and environmental tobacco smoke exposure. Primary outcome (incident chronic bronchitis) analysis additionally adjusted for length of follow-up time. CI, confidence interval; IQR, interquartile range; OR, odds ratio; PM, particulate matter.