Teen e-cigarette use predicts later marijuana use

Hongying Dai

Teenagers who smoke e-cigarettes are more likely to use marijuana in the following year, with young adolescents at an increased risk of heavy use of the drug, according to a study published in Pediatrics.

“There are several possible reasons why younger teenagers who use e-cigarettes may be more prone to later marijuana use,” Hongying Dai, PhD, research faculty and associate professor in health services and outcome research at the Children’s Mercy Hospital and the University of Missouri, Kansas City, told Infectious Diseases in Children. “Their brains are still developing, and nicotine exposure might lead to changes in the central nervous system that predisposes teens to dependence on other drugs.”

“Experimenting with e-cigarettes might also increase youths’ curiosity about marijuana, reduce perceived harm of marijuana use and increase social access to the drug from peers and friends,” she continued. “The adolescent brain has a heightened sensitivity to the rewarding effects of nicotine, and this sensitivity diminishes with age. In addition, younger adolescents tend to have lower impulse control and take risks when compared to older adolescents.”

To assess the relationship between e-cigarette use by adolescents and later marijuana use, the researchers conducted a study of teenagers aged between 12 and 17 years who were included in the Population Assessment of Tobacco and Health study. Those who had reported never using marijuana at wave one (2013-2014) were followed up in a second wave (2014-2015).

Dai and colleagues then performed logistic regressions to identify the link between e-cigarette use during the first wave and ever or heavy marijuana use in the past 12 months and during wave 2.

Of the 10,364 teenagers included in the study, those who had never used marijuana but had used e-cigarettes during wave 1 were more likely to use marijuana within the past 12 months in wave 2 (adjusted OR = 1.9; 95% CI, 1.4-2.5). Adolescents aged between 12 and 14 years were at increased risk of future marijuana use (aOR = 2.7; 95% CI, 1.7-4.3), and a smaller, but present, risk was observed for teenagers aged between 15 and 17 years (aOR = 1.6; 95% CI, 1.2-2.3).

When age was considered in relation to heavy marijuana use, younger adolescents who used e-cigarettes in wave 1 were more likely to use the drug in this manner in wave 2 (aOR = 2.5; 95% CI, 1.2-5.3). The same association was not observed for older teenagers during wave 2.

“Tobacco use in any form is unsafe for youth,” Dai said. “E-cigarettes contain varying levels of nicotine and a number of potentially toxic substances, including some known or suspected carcinogens. For pediatricians, it is important that health screening for youth tobacco use include all tobacco products, especially e-cigarette products. It also is important for pediatricians to advise youth about the risks of e-cigarette use, including the propensity of progression to cigarette, marijuana and other substance use after cigarette use.” – by Katherine Bortz

Disclosures: The authors report no relevant financial disclosures.