E-cigarette use and cigarette smoking initiation among Australian women who have never smoked

Evidence regarding the association between e-cigarette use and subsequent initiation of smoking mostly relates to the US population. In Australia, no studies are available investigating the association between the uses of e-cigarettes and smoking initiation among young adults who have never smoked. This study aimed to determine the association between lifetime e-cigarette use and subsequent initiation of cigarette smoking among tobacco-naïve Australian women aged 20-27.

The current study used data (n = 5398) from the third (2015) and fourth (2016) surveys collected from a cohort of Australian women born in 1989-1995 who participated in the Australian Longitudinal Study on Women's Health. Multivariable logistic regression was used to identify the association between lifetime e-cigarette use at the baseline survey and initiation of cigarette smoking (smoked 100 cigarettes or more in the last year) at the follow up adjusting for possible confounders. Effects were expressed as odds ratios with 95% confidence interval.

The mean (± SD) age of the study participants at baseline (third survey) was 22.5 (±1.7). Ever e-cigarette use at baseline was positively associated with smoking initiation at follow up (adjusted odds ratio 3.71; 95% confidence interval 2.33, 5.93). History of depression, binge drinking and higher childhood adversity score were also risk factors for subsequent smoking initiation in the follow up.

This study identified a strong association between e-cigarette use and subsequent initiation of smoking. Enforcing the existing restriction of sale and supply of e-liquid containing nicotine is essential to prevent never smokers from nicotine addiction via e-cigarettes.