| Variable | Year | Supplement |
|---|---|---|
| ECIGCUR1 | 2015 | Sample adult cancer |
| ECIGCUR2 | 2018 | Sample adult questionnaire |
| ECIGCUR2 | 2017 | Sample adult questionnaire |
| ECIGCUR2 | 2016 | Sample adult questionnaire |
| ECIGED | 2014 | Sample adult questionnaire |
| ECIGNOW_A | 2021 | Sample adult questionnaire |
| ECIGNOW_A | 2020 | Sample adult questionnaire |
| ECIGNOW_A | 2019 | Sample adult questionnaire |