Longitudinal Behavioral Transitions in Adolescent Electronic Nicotine Delivery Systems Use: Markov Multistate...

Many prior studies on adolescent electronic nicotine delivery systems (ENDS) did not differentiate regular users from light users or experimenters. This study was conducted to investigate the longitudinal behavioral transitions among adolescent ENDS users.

Data were drawn from Waves 2, 3, 4, 4.5, and 5 (October 2014-November 2019) of the Population Assessment of Tobacco and Health (PATH) Study and analyzed in 2023. A total of 894 participants (1) who reported at least one day of ENDS use within the past 30 days at any of the waves; and (2) who had ENDS use data on at least 2 different waves were retained in the final analysis sample (N = 894). Markov multistate models were fitted to estimate transition hazard rates between experimental use, nonfrequent use, frequent use, and no use.

Whereas experimental use grew from 2.6% at Wave 2 to 15.4% at Wave 5, nonfrequent use grew from 2.9% to 18.9%, and frequent use grew from 0.3% to 18.8%. Sixty-five percent of experimental use reverted to no use whereas 20% of experimental use progressed to either nonfrequent (12%) or frequent ENDS use (8%) in a year. Once ENDS use is initiated, the percentage progressing to frequent ENDS use jumped to 19% while 20% staying as nonfrequent use in a year. The average past 30-day use frequency of those who reported "fairly regular" use increased over time (6.2 days at Wave 2 to 15.7 days at Wave 5).

These findings demonstrate worrisome tendency of increasing intensity of ENDS use in today's adolescents.