Association of tobacco product use with chronic obstructive pulmonary disease (COPD) prevalence and incidence in Waves 1 through 5 (2013–2019) of the Population Assessment of Tobacco and Health (PATH) Study

Table 4 Association between Wave 1 past 30-day tobacco use and COPD^a incidence Waves 2–5 of the Population Assessment of Tobacco and Health Study

Twelve mutually exclusive categories of Wave 1 tobacco use^b	Weighted Percent with new onset COPD W2-W5 (SE)^c	Covariate adjustment
	Weighted Percent with new onset COPD W2-W5 (SE)^c	Unadjusted (N = 6475)		Cigarette pack-years (N = 6220)		Fully adjusted^d (N = 6018)
Exclusive cigarette as the reference group		COPD incidence (RR)	95% CI	COPD incidence (RR)	95% CI	COPD incidence (RR)	95% CI
Exclusive P30D cigarette	13.4 (0.8)	Ref	Ref	Ref	Ref	Ref	Ref
Never use (Never or former experimental tobacco)	3.8 (0.4)	0.28***	[0.22,0.37]	0.50***	[0.35,0.71]	0.52**	[0.35,0.78]
Former tobacco use	5.5 (0.7)	0.41***	[0.30,0.55]	0.41***	[0.31,0.55]	0.47***	[0.32,0.70]
Exclusive P30D e-cigarette	9.5 (3.5)^†	0.71	[0.28,1.78]	0.63	[0.26,1.49]	0.71	[0.26,1.92]
Exclusive P30D cigar	3.9 (1.2)^†	0.29***	[0.15,0.59]	0.42*	[0.20,0.88]	0.55	[0.24,1.26]
Exclusive P30D smokeless/snus	7.4 (1.7)	0.55*	[0.34,0.90]	0.77	[0.46,1.30]	1.08	[0.58,2.03]
Exclusive P30D cigarette and e-cigarette	14.2 (1.9)	1.06	[0.78,1.45]	1.05	[0.78,1.43]	1.04	[0.77,1.40]
P30D polycombusted tobacco use	15.8 (2.4)	1.18	[0.84,1.66]	1.18	[0.84,1.67]	1.35	[0.92,1.99]
P30D polycombusted and noncombusted use	8.5 (1.7)	0.63*	[0.41,0.98]	0.66	[0.43,1.03]	0.77	[0.50,1.19]

Never tobacco use as the reference group		COPD incidence (RR)	95% CI	COPD incidence (RR)	95% CI	COPD incidence (RR)	95% CI
Never use (Never or former experimental tobacco)	3.8 (0.4)	Ref	Ref	Ref	Ref	Ref	Ref
Former tobacco use	5.5 (0.7)	1.44*	[1.04,2.00]	0.83	[0.56,1.22]	0.90	[0.62,1.33]
Exclusive P30D cigarette	13.4 (0.8)	3.53***	[2.73,4.57]	2.02***	[1.41,2.89]	1.92**	[1.29,2.86]
Exclusive P30D e-cigarette	9.5 (3.5)^†	2.49*	[1.00,6.19]	1.27	[0.54,2.98]	1.36	[0.55,3.39]
Exclusive P30D cigar	3.9 (1.2)^†	1.03	[0.51,2.10]	0.86	[0.42,1.73]	1.05	[0.49,2.25]
Exclusive P30D smokeless/snus	7.4 (1.7)	1.94*	[1.15,3.26]	1.56	[0.91,2.67]	2.08*	[1.07,4.03]
Exclusive P30D cigarette and e-cigarette	14.2 (1.9)	3.74***	[2.74,5.10]	2.13***	[1.48,3.06]	1.99**	[1.29,3.07]
P30D polycombusted tobacco use	15.8 (2.4)	4.17***	[2.87,6.06]	2.39***	[1.55,3.67]	2.59***	[1.60,4.21]
P30D polycombusted and noncombusted use	8.5 (1.7)	2.24***	[1.45,3.45]	1.34	[0.86,2.08]	1.48	[0.92,2.39]

^aCOPD: Chronic Obstructive Pulmonary Disease, defined as self-report of emphysema, chronic bronchitis, or COPD
^bData are not presented for exclusive hookah, exclusive pipe, and dual e-cigarette + smokeless/snus users due to small sample size. Never tobacco user category includes former experimental (e.g., lifetime use of < 100 cigarettes or never used other products fairly regularly) users; former established user category includes all established users (e.g., lifetime use of more than 100 cigarettes or ever used other products fairly regularly) who did not use any tobacco products in the past 30 days
^cOverall cumulative COPD incidence in W2-5 was 5.8% (SE = 0.3)
^dFully adjusted = Risk ratios (RR) are adjusted for cigarette pack-years (never cigarette users were assigned 0 pack-years), past-week secondhand smoke exposure, past 30-day marijuana use, COPD comorbidity index, ever asthma diagnosis, age, sex, race/ethnicity, education, and urbanicity. See Additional file 1: Table S2a and S2b for all covariate estimates
^†Estimate should be interpreted with caution because it has low statistical precision. It is based on a denominator sample size of less than 50, or the coefficient of variation of the estimate or its complement is larger than 30%
*p < 0.05, ** p < 0.01, *** p < 0.001

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