A new study found that adolescents with short-term exclusive cigarette use had a higher risk of incident asthma after 5 years of follow-up.
Adolescents had a higher incidence of incident diagnosed asthma in a 5-year follow-up period, according to a study published in Journal of Adolescent Health. However, an association between exclusive use of electronic nicotine delivery systems (ENDS) or dual use was not found for incident asthma.
Past 30-day cigarette smoking had declined from 4.3% to 1.6% in middle school students and 15.8% to 4.6% in high school students from 2011 to 2020, but the same period saw an increase in ENDS use in middle school (0.6% to 4.7%) and high school students (1.5% to 19.6%). Past studies have evaluated the relationship between tobacco and risk of asthma, but ENDS association remains less known. This study aimed to “investigate whether exclusive and dual use of cigarettes and ENDS was prospectively associated with incident diagnosed asthma among a sample of adolescents as they age into young adulthood.”
Data were used from 2013 to 2019 from the Population Assessment of Tobacco and Health (PATH) study. This was a longitudinal cohort study that evaluated adolescents 12 years and older in the United States that collected data annually from 2013 to 2018 and biannually thereafter. The sample was restricted to adolescents aged 12 to 17 years who did not have asthma at baseline and had at least 1 follow-up interview.
Incident diagnosed asthma was defined as an asthma diagnosis that had been given in the previous 12 months, and either the parents or the child were asked about this status depending on age. Those who reported a recent diagnosis of asthma were classified as incident diagnosed. Current cigarette or ENDS use was defined as having at least 1 cigarette in the previous 30 days. Participants were separated into 4 groups based on usage: never or non-current use, exclusive cigarette use, exclusive ENDS use, and dual use.
Covariates included age, sex, race (Hispanic, non-Hispanic White, non-Hispanic Black, other) and parent education level. Urbanicity, secondhand smoke exposure, household combustible tobacco use, and body mass index were also considered.
There were 9141 participants included in the final sample, with 50.4% aged 15 to 17 years, 50.2% identifying as women, 55.3% who identified as non-Hispanic White, and 79.5% who lived in an urban area. There were 3.1% participants who exclusively smoked cigarettes, 1.7% who exclusively used ENDS, and 1.3% who used both products, although exclusive and dual use of cigarettes and ENDS increased in the follow-ups. Eighty-three percent had never used either cigarettes or ENDS at baseline, 3.0% never used cigarettes and did not currently use ENDS, 4.9% did not currently use cigarettes and never used ENDS, and 2.9% did not currently use cigarettes or ENDS but reported past use.
Adolescents were more likely to be non-Hispanic White if they used cigarettes exclusively or used both products. However, most of the adolescents who did not use either product or exclusively used ENDS were also non-Hispanic White. Those who used both products or smoked cigarettes exclusively had parents with lower education.
In addition, secondhand smoke exposure was also highest in adolescents who exclusively smoked cigarettes (19.3 hours in the past 7 days) compared with adolescents who used both products (16.5 hours), used ENDS exclusively (10.6 hours), or did not use either (3.2 hours).
The hazard of diagnosed asthma was 1.44% overall, which ranged from 0.35% to 2.02% in the 5 years of follow-up. Adolescents who smoked cigarettes exclusively had a 61% higher risk of incident asthma compared with respondents who did not use either product (HR, 1.61; 95% CI, 1.18-2.20).
Those who used ENDS exclusively (HR, 1.19; 95% CI, 0.73-1.96) or in combination with cigarettes (HR, 1.41; 95% CI, 0.86-2.31) did not have statistically different risks compared with those who did not use either. This finding did not differ after adjustment, with adolescents who smoked cigarettes exclusively still having a higher risk of diagnosed asthma (adjusted HR, 1.62; 95% CI, 1.17-2.25) compared with those who had not used cigarettes or ENDS currently.
Data from PATH were self-reported and could have response bias, marking a limitation to these findings. The definition of usage also did not separate experimental and established use, there were also small sample sizes, and allergies, exposure to air pollution, family history of asthma, and physical activity were not used in adjustment.
The researchers concluded that exclusive cigarette use “was associated with higher risk of incident diagnosed asthma in comparison to never or noncurrent cigarette and ENDS use.”
Patel A, Cook S, Mattingly DT, et al. Longitudinal association between exclusive and dual use of cigarettes and electronic nicotine delivery systems and asthma among U.S. adolescents. J Adolesc Health. Published online June 10, 2023. doi:10.1016/j.jadohealth.2023.04.009