Table 3.
Quality of Evidence of Outcomes of Restrictions on the Sale of Flavoured ENDS
| Outcome | Quality of Evidence | Factors that Increase Quality | Factors that Reduce Quality | Supporting Evidence |
|---|---|---|---|---|
| Sale | ||||
| Reduced sales of ENDS | Moderate |
Dose-response gradient (ban on all ENDS vs. flavours) (+ 1) Large magnitude of effect (+ 2) |
Limitations in study design (− 1) Potential publication bias (− 1) |
Ali (2022), Gammon (2021), Katchmar (2021), Liber (2021) [28–31] |
| Increased sales of combustible cigarettes | Low |
Dose-response gradient (ban on all ENDS vs. flavours) (+ 1) Moderate magnitude of effect (+ 1) |
Inconsistent findings (− 1) Limitations in study design (− 1) |
Gammon (2021), Katchmar (2021), Liber (2021), Xu (2022) [28–30, 33] |
| Behaviour | ||||
| Reduced consumption of any tobacco use | Low | Moderate effect sizes across studies (+ 1) |
Inconsistencies in measurement rigour (differing definitions of product use) (− 1) Low measurement rigour (− 1) |
Kingsley (2019, 2021), Olsen (2022), Yang (2022) [38–41] |
| Reduced ENDS consumption | Low | Moderate effect sizes across studies (+ 1) |
Inconsistencies in measurement rigour (differing definitions of product use) (− 1) Low measurement rigour (− 1) |
Hawkins (2021), Kingsley (2019), Liu (2022), Yang (2020) [35, 38, 39, 42] |
| Increased combustible cigarette consumption | Very Low | Large magnitude of effect (+ 2) |
Limitations in study design (− 1) Inconsistency in controls for bias risk (− 1) Inconsistent findings (− 1) Low measurement rigour (differing definitions of product use) (− 1) |
Friedman (2021), Hawkins (2021), Kingsley (2019), Liu (2022), Yang (2022) [34, 35, 38, 39, 42] |
| Compliance | ||||
| Reduced availability of flavoured products | Moderate |
Dose-response gradient (difference in enforcement) (+ 1) Large magnitude of effect across studies (+ 2) |
Limitations in study design (−1) Inconsistencies in measurement rigor (short-term follow-up) (− 1) |
Amalia (2020, 2020), Andersen-Rodgers (2021), Brock (2019), Gaiha (2021), Holmes (2022), Kephart (2020), Kingsley (2019), Nali (2021), Vyas (2021) [39, 53–61] |
The numbers in brackets refer to the extent to which GRADE factors upgraded or downgraded our confidence in the quality of evidence