E-Cigarette Use Was Linked to Asthma in Adolescents, Independent of Marijuana and Cigarette Smoking | Research

The takeaway

Among over 6,000 Hawaiian high school students, current e-cigarette use was independently associated with having asthma, even after controlling for marijuana use and cigarette smoking.

Teens and parents comparing the respiratory risks of different substances.

E-cigarette use was linked to 48% higher odds of current asthma; marijuana was not significant

What the researchers found

In a statewide survey of 6,089 high school students in Hawaii (mean age 15.8), current e-cigarette use was significantly associated with currently having asthma (adjusted OR = 1.48) and with previously having asthma (aOR = 1.22).

Notably, after controlling for e-cigarette use and demographic factors, neither cigarette smoking nor marijuana use were significantly associated with asthma in the multivariate analysis. This suggests that e-cigarettes may have a stronger independent association with asthma than either combustible tobacco or marijuana in this adolescent population.

Racial and ethnic disparities were also observed: Black, Native Hawaiian, other Pacific Islander, and Filipino students had higher rates of asthma compared to Asian American and Caucasian students.

Why it matters

E-cigarettes are frequently marketed as safer alternatives to smoking, including among adolescents. This study adds to growing evidence that e-cigarette aerosol may have significant respiratory health effects. The finding that marijuana was not independently associated with asthma after controlling for e-cigarette use provides context for understanding the relative respiratory risks of different inhalation methods.

The numbers in context

6,089 students. 50% female. Mean age 15.8 years. 33 high schools. Current e-cigarette use and current asthma: aOR = 1.48 (CI 1.26-1.74). E-cigarette use and previous asthma: aOR = 1.22 (CI 1.07-1.40). Marijuana and cigarette smoking: nonsignificant in multivariate model.

How the study worked

Cross-sectional survey administered in classrooms across 33 high schools statewide in Hawaii in 2015. Multinomial regression examined the association between e-cigarette use and asthma, controlling for cigarette smoking, marijuana use, and six demographic covariates.

What this study cannot tell us

Cross-sectional design cannot determine causation: teens with asthma might be more likely to use e-cigarettes (reverse causation) rather than e-cigarettes causing asthma. Self-reported data on both substance use and asthma diagnosis. Hawaii's multiethnic population may not be representative of the broader U.S. The study could not distinguish between nicotine and cannabis vaporizers.

How to read the evidence

Moderate evidence from a large, statewide cross-sectional survey with multivariate analysis.

When this study was published

Published in 2017, using 2015 data from Hawaii.

The bigger picture

This study is notable for what it found about marijuana: after accounting for e-cigarette use, marijuana was not independently associated with asthma in adolescents. This does not mean marijuana is safe for the lungs, but it suggests that in the current landscape of adolescent substance use, e-cigarettes may be a more significant respiratory concern.

Questions still open

Does the direction of causation run from e-cigarettes to asthma or from asthma to e-cigarette use? Would longitudinal studies confirm this association? What specific components of e-cigarette aerosol contribute to respiratory effects?

Common questions

Does this mean marijuana is safer for the lungs than e-cigarettes?

Not necessarily. This cross-sectional study found e-cigarette use was more strongly associated with asthma than marijuana in this teen sample, but it cannot prove causation in either direction. Marijuana smoke does contain harmful compounds, and this single study does not override the broader evidence on respiratory risks.

Can e-cigarettes cause asthma?

This study found an association but cannot prove causation. It is possible that e-cigarettes contribute to asthma, but it is also possible that teens with asthma are more likely to try e-cigarettes. Longitudinal studies tracking teens over time would be needed to determine the direction of causation.

Read the original research

E-cigarette use and asthma in a multiethnic sample of adolescents.

Preventive medicine, 105, 226-231

View on PubMed ↗Publisher’s paper ↗

Citation

Schweitzer, Rebecca J; Wills, Thomas A; Tam, Elizabeth; Pagano, Ian; Choi, Kelvin. (2017). E-cigarette use and asthma in a multiethnic sample of adolescents.. Preventive medicine, 105, 226-231. https://doi.org/10.1016/j.ypmed.2017.09.023