Electronic Nicotine Delivery System flavor use over time by age group in the US: A longitudinal analysis.

INTRODUCTION: The prevalence of flavor use in Electronic Nicotine Delivery Systems (ENDS) has been assessed in numerous studies, but limited research has focused on flavor use trends and maintenance of flavor preference over time. This study investigated the general trends and maintenance of ENDS flavor use for youth (aged 12-17 years), young adults (aged 18-24 years), and older adults (aged ≥25 years) between 2014 and 2019. METHODS: Population Assessment of Tobacco and Health (PATH) Study Wave 2 (2014-2015), Wave 3 (2015-2016), Wave 4 (2016-2017), and Wave 5 (2018-2019) youth and adult data were used. Cross-sectional flavor use prevalence (trends) and flavor maintenance (using the same flavor category in at least three consecutive waves) were assessed. RESULTS: The most reported primary flavor category was fruit among all age groups in all waves. Candy/desserts in waves two, three, four, and menthol/mint in wave five were the second most reported flavor in all age groups. The highest increase was observed for menthol/mint use among youth between wave two (21.9%) and five (58.1%) (OR=5.33; 95% CI: 3.58-7.96). Overall, 37.6% of fruit flavor users, 25.3% of candy/desserts users, 32.0% of menthol/mint users, and 33.4% of tobacco flavor users, maintained use of the same flavor in at least three consecutive waves. CONCLUSIONS: Fruit flavor had the highest percentages of use and maintenance between 2014 and 2019. While the maintenance of fruit and candy/desserts flavors were higher among youth, adults had substantially higher maintenance percentages for menthol/mint and tobacco flavor. There was a substantial increase in menthol/mint use in wave five among youth, which may affect ENDS flavor maintenance patterns in the future. Understanding maintenance of flavors over time can inform regulation of ENDS flavors.