Covariate HRs for adults and youth in 2015–2017 and 2017–2019 in multivariable multistate transition models
| Male versus female | Age 12–14 years vs 15–17 years | Age 18–24 years vs 35–54 years | Age 25–34 years vs 35–54 years | Age 55–90 years vs 35–54 years | Non-Hispanic black versus non-Hispanic white | Hispanic versus Non-Hispanic white | Non-daily versus daily cigarette use | Non-daily versus daily ENDS use | |
| Never to cigarette | |||||||||
| Adults 2015–2017 | 1.74 (1.29 to 2.35) | – | 2.13 (1.41 to 3.23) | 1.32 (0.84 to 2.06) | 0.71 (0.43 to 1.16) | 2.97 (1.92 to 4.61) | 3.61 (2.31 to 5.65) | – | – |
| Adults 2017–2019 | 1.23 (0.69 to 2.20) | – | 2.58 (1.32 to 5.05) | 2.11 (0.84 to 5.31) | 0.81 (0.25 to 1.87) | 0.69 (0.32 to 1.50) | 1.93 (0.97 to 3.86) | – | – |
| Youth 2015–2017 | 0.63 (0.24 to 1.62) | 0.26 (0.08 to 0.91) | – | – | – | 0.98 (0.39 to 2.48) | * | – | – |
| Youth 2017–2019 | 0.42 (0.12 to 1.56) | 0.26 (0.07 to 0.99) | – | – | – | 0.59 (0.20 to 1.78) | * | – | – |
| Never to ENDS | |||||||||
| Adults 2015–2017 | 2.61 (1.63 to 4.19) | – | 20.1 (4.59 to 87.6) | 4.18 (1.02 to 17.1) | * | 1.31 (0.74 to 2.30) | 1.12 (0.53 to 2.37) | – | – |
| Adults 2017–2019 | 1.97 (1.41 to 2.76) | – | 82.2 (13.3 to 509) | 8.95 (1.31 to 61.3) | * | 0.57 (0.37 to 0.88) | 0.74 (0.35 to 1.59) | – | – |
| Youth 2015–2017 | 1.83 (1.19 to 2.81) | 0.30 (0.05 to 1.78) | – | – | – | 0.55 (0.34 to 0.91) | * | – | – |
| Youth 2017–2019 | 1.44 (1.17 to 1.78) | 0.26 (0.20 to 0.33) | – | – | – | 0.35 (0.26 to 0.46) | 0.33 (0.19 to 0.59) | – | – |
| Non-current to cigarette | |||||||||
| Adults 2015–2017 | 0.90 (0.73 to 1.10) | – | 4.77 (3.66 to 6.21) | 3.02 (2.38 to 3.85) | 0.40 (0.29 to 0.56) | 1.08 (0.85 to 1.37) | 1.19 (0.91 to 1.55) | – | – |
| Adults 2017–2019 | 0.85 (0.68 to 1.07) | – | 3.20 (2.40 to 4.27) | 2.60 (1.94 to 3.49) | 0.34 (0.24 to 0.47) | 1.16 (0.76 to 1.76) | 1.58 (1.14 to 2.20) | – | – |
| Youth 2015–2017 | * | * | – | – | – | * | * | – | – |
| Youth 2017–2019 | 1.12 (0.48 to 2.60) | 2.35 (0.61 to 9.14) | – | – | – | 0.87 (0.22 to 3.53) | * | – | – |
| Non-current to ENDS | |||||||||
| Adults 2015–2017 | 0.98 (0.60 to 1.62) | – | 9.48 (5.48 to 16.4) | 2.24 (1.13 to 4.47) | 0.25 (0.11 to 0.54) | 1.03 (0.55 to 1.94) | 2.16 (1.00 to 4.66) | – | – |
| Adults 2017–2019 | 0.81 (0.52 to 1.25) | – | 22.2 (14.0 to 35.2) | 2.98 (1.80 to 4.95) | 0.36 (0.12 to 1.10) | 0.88 (0. 50 to 1.53) | 0.90 (0.42 to 1.94) | – | – |
| Youth 2015–2017 | 1.02 (0.29 to 3.57) | * | – | – | – | * | * | – | – |
| Youth 2017–2019 | 2.28 (0.90 to 5.75) | 0.43 (0.09 to 2.11) | – | – | – | 0.58 (0.26 to 1.32) | * | – | – |
| Cigarette to non-current | |||||||||
| Adults 2015–2017 | 1.01 (0.85 to 1.21) | – | 1.75 (1.44 to 2.13) | 1.49 (1.23 to 1.82) | 1.22 (0.98 to 1.54) | 1.07 (0.85 to 1.35) | 0.67 (0.53 to 0.85) | 4.69 (4.08 to 5.39) | – |
| Adults 2017–2019 | 1.01 (0.84 to 1.22) | – | 1.49 (1.14 to 1.96) | 1.16 (0.94 to 1.45) | 1.11 (0.85 to 1.45) | 1.06 (0.83 to 1.36) | 0.57 (0.43 to 0.76) | 4.32 (3.66 to 5.11) | – |
| Youth 2015–2017 | 1.36 (0.24 to 7.67) | * | – | – | – | * | 0.92 (0.17 to 4.88) | 2.02 (0.42 to 9.66) | – |
| Youth 2017–2019 | 0.73 (0.11 to 4.75) | * | – | – | – | 1.12 (0.12 to 10.3) | * | * | – |
| Cigarette to dual | |||||||||
| Adults 2015–2017 | 0.90 (0.72 to 1.14) | – | 2.50 (1.65 to 3.76) | 1.64 (1.25 to 2.15) | 0.40 (0.26 to 0.61) | 0.68 (0.47 to 0.98) | 0.48 (0.32 to 0.72) | * | – |
| Adults 2017–2019 | 0.90 (0.71 to 1.15) | – | 3.17 (2.20 to 4.55) | 1.57 (1.02 to 2.41) | 0.38 (0.21 to 0.70) | 0.75 (0.47 to 1.20) | 0.61 (0.33 to 1.14) | * | – |
| Youth 2015–2017 | * | * | – | – | – | * | * | * | – |
| Youth 2017–2019 | * | * | – | – | – | * | * | * | – |
| ENDS to non-current | |||||||||
| Adults 2015–2017 | 0.60 (0.43 to 0.83) | – | 2.16 (1.46 to 3.20) | 1.05 (0.68 to 1.59) | 0.42 (0.23 to 0.77) | 2.32 (1.69 to 3.18) | 2.67 (1.63 to 4.39) | – | 1.13 (0.22 to 5.79) |
| Adults 2017–2019 | 0.80 (0.56 to 1.13) | – | 2.20 (1.33 to 3.64) | 1.32 (0.73 to 2.39) | 1.01 (0.52 to 1.98) | 1.43 (0.89 to 2.28) | 1.59 (0.89 to 2.85) | – | 1.39 (0.61 to 3.18) |
| Youth 2015–2017 | 1.14 (0.46 to 2.79) | 1.42 (0.22 to 9.2) | – | – | – | * | * | – | 9.52 (1.56 to 58.0) |
| Youth 2017–2019 | 1.66 (0.94 to 2.92) | 1.84 (1.07 to 3.17) | – | – | – | 1.00 (0.48 to 1.71) | 1.86 (0.28 to 12.5) | – | * |
| ENDS to dual | |||||||||
| Adults 2015–2017 | 1.25 (0.87 to 1.83) | – | 0.82 (0.48 to 1.39) | 0.78 (0.48 to 1.24) | 0.41 (0.21 to 0.83) | 0.85 (0.49 to 1.49) | 0.61 (0.24 to 1.52) | – | * |
| Adults 2017–2019 | 0.97 (0.60 to 1.55) | – | 1.20 (0.62 to 2.34) | 1.54 (0.69 to 3.42) | 0.67 (0.24 to 1.87) | 0.99 (0.52 to 1.89) | * | – | * |
| Youth 2015–2017 | 0.90 (0.24 to 3.28) | * | – | – | – | 0.72 (0.14 to 3.84) | * | – | * |
| Youth 2017–2019 | 1.49 (0.58 to 3.87) | * | – | – | – | * | 3.47 (0.64 to 18.6) | – | * |
| Dual to cigarette | |||||||||
| Adults 2015–2017 | 1.07 (0.87 to 1.32) | – | 1.18 (0.90 to 1.57) | 0.98 (0.76 to 1.26) | 0.84 (0.64, 1.09) | 1.17 (0.83 to 1.64) | 0.98 (0.62 to 1.55) | 0.57 (0.41 to 0.80) | 0.98 (0.69 to 1.41) |
| Adults 2017–2019 | 0.90 (0.63 to 1.26) | – | 0.73 (0.47 to 1.14) | 0.93 (0.60 to 1.46) | 1.42 (0.92 to 2.19) | 1.11 (0.71 to 1.74) | 0.99 (0.55 to 1.77) | 0.97 (0.59 to 1.58) | 0.53 (0.36 to 0.78) |
| Youth 2015–2017 | * | * | – | – | – | * | * | * | * |
| Youth 2017–2019 | * | * | – | – | – | * | * | * | * |
| Dual to ENDS | |||||||||
| Adults 2015–2017 | 0.98 (0.49 to 1.95) | – | 1.32 (0.64 to 2.71) | 0.94 (0.50 to 1.76) | 0.57 (0.16 to 2.07) | 0.91 (0.48 to 1.71) | 0.87 (0.27 to 2.82) | * | * |
| Adults 2017–2019 | 1.01 (0.55 to 1.87) | – | 5.48 (2.40 to 12.5) | 3.37 (1.28 to 8.89) | 1.62 (0.41 to 6.43) | 0.65 (0.24 to 1.76) | 1.47 (0.49 to 4.40) | 1.20 (0.43 to 3.33) | 3.70 (1.29 to 10.6) |
| Youth 2015–2017 | * | * | – | – | – | * | * | * | * |
| Youth 2017–2019 | * | * | – | – | – | * | * | * | * |
Boldfaced values are statistically significantly different from 1.0 at level of significance 0.05.
*Estimate suppressed because of high variance (variance of log(HR) >1).
ENDS, electronic nicotine delivery system.