E-cigarette use is associated with increased risk of tobacco cigarette initiation and use, particularly among low-risk US youths, a new study found. The prospective cohort study used data from waves 1 through 3 of the Population Assessment of Tobacco and Health Study (2013-2016) to assess youths aged 12-15 years who had never used cigarettes, e-cigarettes, or other tobacco products at wave 1. The primary outcome was ever cigarette use and current cigarette use at wave 3. Researchers found:

• The sample included 6,123 respondents (49.5% female, 54.1% non-Hispanic, white; mean age 13.4 years).
• Of these, 8.6% reported e-cigarettes as their first tobacco product, while 5.0% reported using another noncigarette product first, and 3.3% reported using cigarettes first.
• Youths whose first tobacco product was an e-cigarette were more likely to initiate cigarettes over 2 years of follow-up.
• Over the 2 years between 2013-2014 and 2015-2016, 21.8% of new cigarette ever use and 15.3% of current cigarette use among US youths aged 12-15 years may be attributable to prior e-cigarette use.