Dual use of cigarettes, e-cigarettes negatively impacts abstinence likelihood

Key takeaways:

• At each follow-up, the proportion of individuals moving to nicotine abstinence was always lower in the baseline dual user group.
• The switch from dual use to exclusive cigarette use was common.

A smaller proportion of individuals who used both e-cigarettes and cigarettes achieved nicotine abstinence vs. individuals who used only cigarettes or only e-cigarettes, according to results published in ERJ Open Research.

“Given these findings, we believe that dual use might prove to be a major hinderance in achieving smoking abstinence and this practice should not be recommended for treating nicotine addiction,” Josef Hamoud, of the University Medical Center Gttingen in Germany, said in a press release.

“In addition, while long term health effects of vapes need to be studied further, the double exposure to large amounts of nicotine and toxicants from both conventional cigarettes and vapes are a great concern for public health,” Hamoud continued.

After searching two databases, Hamoud and colleagues examined 16 longitudinal, observational studies (12 studies in adults; four in youth/adolescents) of individuals who reported dual e-cigarette and cigarette use (n = 2,432) vs. e-cigarette only use and cigarette only use to determine how dual use impacts smoking cessation.

The degree of heterogeneity in the studies was found to be “great,” according to researchers. Additionally, the risk of bias was stated to be moderate to high.

Notably, the meta-analysis factored in findings from eight of the 16 studies.

“Four studies among adult populations could not be included for meta-analysis due to clinical diversity and methodological heterogeneity,” Hamoud and colleagues wrote.

An identical explanation was given for not including the four studies involving adolescents.

Among individuals who made a switch from using both e-cigarettes and cigarettes, researchers reported that exclusive cigarette smoking was often what they transitioned to using. At a 4-to-8-month follow-up, the proportion of individuals who fit this description was 30%, and as more time passed, this went up (> 8 to 16 months, 47%; > 16 to 24 months, 58%; > 24 to 48 months, 55%).

Although cigarette use among baseline dual users fell from 90% at 4 to 8 months to 63% at greater than 24 to 48 months, this proportion was still considered high by researchers.

In terms of complete abstinence, there was a lower likelihood for this outcome among individuals who used both e-cigarettes and cigarettes at baseline vs. individuals who used only cigarettes or only e-cigarettes, according to the study.

At each follow-up, the proportion of individuals moving to nicotine abstinence was always lower in the baseline dual user group vs. the baseline cigarette only and e-cigarette only groups (4 to 8 months, 3% vs. 6% and 8%; 8 to 16 months, 5% vs. 7% and 19%; 16 to 24 months, 13% vs. 17% and 26%; 24 to 48 months, 24% vs. 25% and 34%).

During a 16-to-24-month follow-up in the dual user group, researchers observed that 19% continued to use both e-cigarettes and cigarettes, and this went down to 8% by the 24-to-48-month follow-up.

“While it may have been argued that heavy smokers might benefit from dual use by reducing their daily cigarette consumption, the high nicotine content of vapes adds to the risk of continued nicotine addiction,” Hamoud said in the release. “Future studies must further stratify dual-use groups to investigate the health implications over time.”

Reference:

• People who use vapes as well as cigarettes are less likely to quit and often switch to just smoking. https://www.eurekalert.org/news-releases/1066330. Published Dec. 4, 2024. Accessed Dec. 4, 2024.