An update of a systematic review and meta‐analyses exploring flavours in intervention studies of e‐cigarettes for smoking cessation.

Aims Methods Results Conclusions To determine patterns of e‐cigarette flavour use (sweet, tobacco, menthol/mint) in interventional studies of e‐cigarettes for stopping smoking, and to estimate associations between flavours and smoking/vaping outcomes.Update of secondary data analyses, including meta‐analyses subgrouped by flavour provision and narrative syntheses, incorporating data from January 2004 to February 2024. Eligible studies were identified from a Cochrane review. Studies provided adults who smoked cigarettes with nicotine‐containing e‐cigarettes for smoking cessation and provided data on e‐cigarette e‐liquid flavour use. Outcomes included participants' flavour use measured at any time, plus smoking abstinence, abstinence from all tobacco or commercial nicotine products and allocated product use at 6 months or longer, reported as risk ratios with 95% confidence intervals. We assessed risk of bias using the Cochrane Risk of Bias 1 tool.We included 25 studies (<italic>n</italic> = 16 748); 21 contributed to subgroup meta‐analyses and 18 provided flavour choices. We judged 15 studies at high, seven at low and three at unclear risk of bias. In studies where participants had a choice of flavours, some switching between flavours occurred (five studies). A preference for sweet (including fruit) flavours over tobacco and menthol was indicated (in 6 of 11 studies); however, there were differences across studies. Subgroup meta‐analyses showed no clear associations between e‐liquid flavours provided and smoking cessation or study product use. One included study randomised participants to two different flavour conditions and found similar cessation rates and long‐term e‐cigarette use between arms at 12 months.Some people using e‐cigarettes to quit smoking switch between e‐cigarette flavours during a quit attempt. Sweet flavours may be preferred overall, but this may differ depending on context. Based on intervention studies, there is no clear association between the use of e‐cigarette flavours and smoking cessation or longer‐term e‐cigarette use, possibly due to a paucity of data. [ABSTRACT FROM AUTHOR]