Table 4.
Association between Wave 1 past 30-day tobacco use and COPDa incidence Waves 2–5 of the Population Assessment of Tobacco and Health Study
| Twelve mutually exclusive categories of Wave 1 tobacco useb | Weighted Percent with new onset COPD W2-W5 (SE)c | Covariate adjustment | |||||
|---|---|---|---|---|---|---|---|
| Unadjusted (N = 6475) |
Cigarette pack-years (N = 6220) |
Fully adjustedd (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