TABLE 2.
Characteristics of included studies.
| Study ID | Device type a | Total N (baseline) | Groups reported | Outcomes available (time‐point) | Data type | Overall risk of bias judgement | Tobacco or EC industry funding? (Y/N) | Country |
|---|---|---|---|---|---|---|---|---|
| Cobb et al. 2021 [7] | Cartridge | 520 | Covariates include CC and EC use | eCO (3 months) | Absolute values at follow‐up | Low | N | USA |
| Cravo et al. 2016 [8] | Cig‐a‐like | 419 | EC and CC | Multiple biomarkers (1 week) | Change from baseline | High | Y | UK |
| Goniewicz et al. 2017 [9] | Cig‐a‐like | 22 | EC and dual use | Multiple biomarkers (1 and 2 weeks) | Change from baseline | High | N | Poland |
| Ikonomidis et al. 2018 [10] | Not clear | 90 | EC, CC and dual use | eCO (1 month) | Absolute values at follow‐up | High | N | Greece |
| Kerr 2020 [5] | Refillable | 55 | EC and abstainers | eCO (12 weeks) | Absolute values at follow‐up | High | N | UK |
| McRobbie et al. 2015 [11] | Cig‐a‐like | 40 | EC, CC and dual use | 3‐HPMA (4 weeks) | Change from baseline | High | N | UK |
| Morris et al. 2022 [6] | Pod | 79 | EC, CC and dual use | eCO and multiple biomarkers (2 weeks) | Absolute values at follow‐up | High | Y | USA |
| Pacifici et al.2015 [12] | Refillable | 34 | EC, CC and dual use | eCO (1, 4, 8 months) | Absolute values at follow‐up | High | N | Italy |
| Pulvers et al. 2018 [13] | Refillable | 40 | EC and dual use | Multiple biomarkers (4 weeks) | Change from baseline | High | N | USA |
a
Based on classification in Hartmann‐Boyce et al. [4]; more information on product characteristics in each study can be found in the Cochrane review. Y/N = yes/no; EC = electronic cigarette; CC = combustible cigarette; eCO = exhaled carbon monoxide; HPMA = hydroxypropylmercapturic acid.