Transitions between smoking and vaping: Evidence (or lack thereof) on potential differences by gender and sex

To synthesize existing evidence on possible differential effects by sex and gender from two Cochrane reviews evaluating vaping and smoking transitions.

We screened included studies from two Cochrane reviews for studies reporting smoking outcomes based on gender or sex. The first review examines the effects of using e-cigarettes to help people quit smoking and includes randomized controlled trials and uncontrolled intervention studies published to July 2023. The second review aims to assess the evidence on the relationship between the use and availability of e-cigarettes and subsequent smoking in young people (aged 29 and younger) and includes quasi-experimental and cohort studies published to April 2023. Due to the paucity and heterogeneity of data, we report results narratively.

10 of 161 studies included in the two relevant reviews met our criteria. Only five reported analyzing whether observed effects or associations varied based on sex and/or gender. A further three provided relevant descriptive information, and two did not report overall outcomes regarding vaping and smoking transitions but did investigate whether these differed by sex/gender. Synthesized data were largely inconclusive, but there was some suggestion that vaping was more strongly associated with subsequent smoking in young males than females. No studies reported data on nonbinary participants.

Despite plausible reasons why sex and gender may be moderators of vaping and smoking transitions, there is little evidence investigating this. Future studies of vaping and smoking transitions should conduct and report analyses investigating potential differences based on sex and gender.