Table 7.

Hazard ratios for death stratified by smoking status according to PM₁₀ exposure duration (1 month).

	N	HR	95% CI		aHR	95% CI
1 month
Never smokers
Total COPD	3,348	1.046	1.021	1.072	1.028	1.009	1.049
Pure COPD	1,678 (52.67)	1.040	1.002	1.079	1.012	0.984	1.041
ACO	1,670 (53.41)	1.051	1.017	1.086	1.040	1.014	1.068
Former smokers
Total COPD	967	0.981	0.940	1.023	0.999	0.963	1.036
Pure COPD	502 (15.76)	1.070	1.014	1.129	1.045	0.997	1.095
ACO	465 (14.87)	0.908	0.859	0.960	0.940	0.893	0.988
Current smokers
Total COPD	1,998	1.040	1.016	1.065	1.025	1.004	1.046
Pure COPD	1,006 (31.58)	1.015	0.980	1.050	1.006	0.977	1.036
ACO	992 (31.72)	1.062	1.031	1.094	1.039	1.011	1.068

COPD = chronic obstructive pulmonary disease, ACO = asthma-COPD overlap, HR = hazard ratio, CI = confidence interval.

*Adjusted by sex, age, Charlson Comorbidity Index, body mass index, and household income level.