Aim: To determine if associations exist between electronic cigarette (E-cigarette) use and various health behaviours after adjusting for current tobacco smoking status.
Background: E-cigarettes are battery powered devices that heat a liquid to a vapour so it can be inhaled. The liquid may contain nicotine. The prevalence of e-cigarette use in NSW has previously been reported to higher in current tobacco smokers compared to non-smokers1.
Method: E-cigarette use amongst adults aged 16 years and over was captured in the NSW Population Health Survey from 2014 to 2017. Methods for the survey have been described elsewhere (Barr et al, 2012). Odds ratios were calculated using the Proc Surveylogistic procedure in SAS 9.4. The following health behaviours were studied: alcohol consumption, adequate fruit intake, lifetime cannabis use, and overweight or obesity.
Results: In NSW, across 2014-2017, the prevalence of current smoking was 14.8% (95%CI: 14.3%-15.4%) and the prevalence of current e-cigarette use was 1.01% (95%CI: 0.87% - 1.16%). Amongst current e-cigarette users, 52% were current smokers. Significant crude associations were found between current e-cigarette use and alcohol consumption, inadequate fruit consumption, overweight or obesity, and lifetime cannabis use. However, when the models were adjusted for current smoking, significant associations remained only for cannabis use (OR: 2.61, 95%CI: 1.39-4.88) and overweight or obesity (OR: 1.58, 95%CI: 1.15-2.18). No significant interactions were found between current smoking and current e-cigarette use.
Conclusion: Due to high rates of tobacco use among electronic cigarette users, it is prudent to adjust for tobacco use in e-cigarette association studies.