Table 6.

Hazard ratios for death stratified by smoking status according to PM₁₀ exposure duration (3 months).

	N	HR	95% CI		aHR	95% CI
3 months
Never smokers
Total COPD	3,348	1.176	1.160	1.192	1.123	1.106	1.141
Pure COPD	1,678 (52.67)	1.171	1.148	1.194	1.103	1.075	1.131
ACO	1,670 (53.41)	1.180	1.158	1.202	1.151	1.124	1.178
Former smokers
Total COPD	967	1.165	1.138	1.192	1.143	1.104	1.183
Pure COPD	502 (15.76)	1.169	1.135	1.204	1.166	1.098	1.237
ACO	465 (14.87)	1.174	1.122	1.229	1.150	1.088	1.215
Current smokers
Total COPD	1,998	1.155	1.141	1.169	1.127	1.110	1.145
Pure COPD	1,006 (31.58)	1.161	1.142	1.182	1.137	1.111	1.164
ACO	992 (31.72)	1.148	1.128	1.168	1.124	1.097	1.152

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.