Summary of transitions in P30D tobacco use at W3 (2015/16) among W1 (2013/14) never tobacco users who initiate electronic nicotine delivery system (ENDS)* use at W2 (2014/15)
| Pathways | Youth | Young Adults | Adults 25+ | |||||||||
| Unweighted Sample Size | Weighted Sample Size | Weighted % | CI | Unweighted Sample Size | Weighted Sample Size | Weighted % | CI | Unweighted Sample Size | Weighted Sample Size | Weighted % | CI | |
| W2 Initiate Exclusive ENDS - W3 No Tobacco | 64 | 146,973 | 59 | (48.4-68.8) | 11 | 92,281 | 91.3† | (53.3-99.0) | - | - | - | - |
| W2 Initiate Exclusive ENDS - W3 Exclusive ENDS | 20 | 48,948 | 19.7 | (12.5-29.6) | 1 | 8,769 | 8.7† | (1.0-46.7) | 1 | 16,096 | 100.0† | (.-.) |
| W2 Initiate Exclusive ENDS - W3 Exclusive CIGS | 1 | 2,370 | 1.0† | (0.1-7.2) | - | - | - | - | - | - | - | - |
| W2 Initiate Exclusive ENDS - W3 CIGS+ENDS PTU | 8 | 23,229 | 9.3† | (4.4-18.7) | - | - | - | - | - | - | - | - |
| W2 Initiate Exclusive ENDS - W3 ENDS PTU w/o CIGS | 5 | 12,240 | 4.9† | (1.9-12.3) | - | - | - | - | - | - | - | - |
| W2 Initiate Exclusive ENDS - W3 CIGS PTU w/o ENDS | 2 | 4,273 | 1.7† | (0.4-7.5) | - | - | - | - | - | - | - | - |
| W2 Initiate Exclusive ENDS - W3 Non-ENDS/Non-CIGS | 5 | 10,961 | 4.4† | (1.8-10.4) | - | - | - | - | - | - | - | - |
| W2 Initiate CIGS+ENDS PTU - W3 No Tobacco | 11 | 23,050 | 28.5† | (16.7-44.3) | 3 | 16,196 | 20.6† | (4.0-61.4) | - | - | - | - |
| W2 Initiate CIGS+ENDS PTU - W3 CIGS+ENDS PTU | 12 | 26,231 | 32.5† | (20.3-47.6) | 2 | 15,953 | 20.3† | (3.7-62.5) | - | - | - | - |
| W2 Initiate CIGS+ENDS PTU - W3 Exclusive ENDS | 1 | 3,360 | 4.2† | (0.6-24.3) | 2 | 18,771 | 23.9† | (4.8-66.2) | - | - | - | - |
| W2 Initiate CIGS+ENDS PTU - W3 Exclusive CIGS | 7 | 15,447 | 19.1† | (9.5-34.7) | 1 | 11,275 | 14.3† | (1.9-59.3) | - | - | - | - |
| W2 Initiate CIGS+ENDS PTU - W3 ENDS PTU w/o CIGS | 2 | 3,997 | 5.0† | (1.2-18.3) | - | - | - | - | - | - | - | - |
| W2 Initiate CIGS+ENDS PTU - W3 CIGS PTU w/o ENDS | 1 | 3,018 | 3.7† | (0.4-27.8) | 3 | 16,509 | 21.0† | (5.6-54.1) | - | - | - | - |
| W2 Initiate CIGS+ENDS PTU - W3 Non-ENDS/Non-CIGS | 2 | 5,640 | 7.0† | (1.7-24.2) | - | - | - | - | - | - | - | - |
| W2 Initiate ENDS PTU w/o CIGS - W3 No Tobacco | 3 | 7,172 | 13.3† | (3.6-38.6) | 2 | 12,675 | 41.2† | (6.8-87.1) | - | - | - | - |
| W2 Initiate ENDS PTU w/o CIGS - W3 ENDS PTU w/o CIGS | 2 | 2,360 | 4.4† | (1.1-15.5) | 1 | 5,777 | 18.8† | (1.6-76.3) | - | - | - | - |
| W2 Initiate ENDS PTU w/o CIGS - W3 Exclusive ENDS | 8 | 18,497 | 34.2† | (17.5-55.9) | - | - | - | - | - | - | - | - |
| W2 Initiate ENDS PTU w/o CIGS - W3 Exclusive CIGS | 1 | 2,221 | 4.1† | (0.5-25.3) | 1 | 12,331 | 40.1† | (5.7-88.0) | - | - | - | - |
| W2 Initiate ENDS PTU w/o CIGS - W3 CIGS+ENDS PTU | 6 | 14,920 | 27.6† | (11.0-53.8) | - | - | - | - | - | - | - | - |
| W2 Initiate ENDS PTU w/o CIGS - W3 CIGS PTU w/o ENDS | 1 | 1,362 | 2.5† | (0.3-17.5) | - | - | - | - | - | - | - | - |
| W2 Initiate ENDS PTU w/o CIGS - W3 Non-ENDS/Non-CIGS | 3 | 7,592 | 14.0† | (3.8-40.2) | - | - | - | - | - | - | - | - |
Analysis included youth (ages 12-17), young adult (ages 18-24), and adult 25+ (ages 25 and older) W1 never tobacco users who initiated ENDS use at W2 with data at all three waves. Respondent age was calculated based on age at W1. W3 longitudinal (all-waves) weights were used to calculate estimates.
W3 tobacco use groups among W1 never tobacco users who initiate ENDS use at W2:
1) No tobacco: Defined as no use of any tobacco products within the past 30 days.
2) Exclusive CIGS: Defined as use of only cigarettes in the past 30 days.
3) Exclusive ENDS: Defined as use of only ENDS in the past 30 days.
4) CIGS+ENDS PTU: Defined as use of only both cigarettes and ENDS in the past 30 days.
5) CIGS PTU w/o ENDS: Defined as use of cigarettes and any other tobacco product(s) except for ENDS in the past 30 days.
6) ENDS PTU w/o CIGS: Defined as use of ENDS and any other tobacco product(s) except for cigarettes in the past 30 days.
7) Non-CIGS, Non-ENDS: Defined as use of one or more tobacco products, excluding cigarettes and ENDS in the past 30 days.
*Respondents were asked about “e-cigarettes” at W1 and “e-products” (i.e., e-cigarettes, e-cigars, e-pipes, and e-hookah) at W2 and W3.
The logit-transformation method was used to calculate confidence intervals.
†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%.
Analyses were run on the W1, W2, and W3 Public Use Files (https://doi.org/10.3886/ICPSR36498.v8).
-, not applicable because of zero cases; +, and; CI, confidence interval; CIGS, cigarettes; ENDS, electronic nicotine delivery system; P30D, past 30-day; PTU, polytobacco use; W1, Wave 1; W2, Wave 2; W3, Wave 3; w/o, without.