TOPLINE

Increases in e-cigarette uptake were observed among young adults aged 18-24 years in the US from 2019 to 2024, with more than 16% of those who used only cigarettes transitioning to dual use of cigarettes and electronic nicotine delivery systems per year in 2022-2024. Rates of transitions from dual use to exclusive use of electronic nicotine delivery systems were higher among young adults and adults aged 25-34 years.

METHODOLOGY

• Researchers analyzed data from the Population Assessment of Tobacco and Health Study collected over survey waves from 2021 to 2024 to estimate product transition rates and transition probabilities per year, overall and across age groups.
• A total of 23,803 adults were included in the March 2021-April 2023 analysis and 24,756 adults in the January 2022-December 2024 analysis, with participants categorized on the basis of age, sex, and race and ethnicity.
• The use of products was classified as use that was never established, noncurrent use, use of cigarettes only, use of electronic nicotine delivery systems only, or dual use.
• Current use involved prior established usage and use of the product within the past month. Noncurrent use meant that neither product was used in the preceding 30 days by an individual who had previously been using one or both products. Established use of cigarettes required smoking 100 or more cigarettes in a lifetime; established vaping required consistent use of electronic nicotine delivery systems.

TAKEAWAY

• The initiation of electronic nicotine delivery systems increased from 0.3% (95% CI, 0.3%-0.4%) per year in the 2019-2022 period to 0.5% (95% CI, 0.4%-0.6%) in 2021-2022 and subsequently dropped back to 0.3% (95% CI, 0.3%-0.4%) in 2022-2024, with 1.7% (95% CI, 1.4%-2.0%) of young adults initiating electronic nicotine delivery systems in 2022-2024.
• Transitions from cigarette-only use to dual use changed from 4.0% in 2019-2021 to 6.8% in 2021-2022 and to 5.9% in 2022-2024, with 16.2% of young adults transitioning to dual use in 2022-2024.
• The rate of transitions from dual use to cigarette-only use fell from 26.2% in 2021-2022 to 17.3% in 2022-2024. Transitions from dual use to exclusive use of electronic nicotine delivery systems rose from 17.0% in 2019-2021 to 24.2% in 2021-2022, with higher rates among those aged 18-24 years (34.4%) and those aged 25-34 years (29.4%).
• Adults who smoked cigarettes intermittently were more likely to transition to noncurrent use than those who smoked daily (2022-2024: hazard ratio [HR], 4.13; 95% CI, 3.02-5.63). Similarly, among adults using both products, those who smoked cigarettes intermittently had elevated rates of switching to electronic nicotine delivery systems exclusively (HR, 2.52; 95% CI, 1.63-3.91).

IN PRACTICE

"The results highlight an important challenge for those promoting transitions along the longer-term trajectory of cigarette-only to dual use to ENDS [electronic nicotine delivery systems]-only use to non-current use for people who smoke cigarettes and would not otherwise quit: successful transitions from dual to ENDS-only use are more likely among those frequently using ENDS, but frequent ENDS use is associated with reduced ENDS cessation," the researchers wrote.

"Public health efforts targeting older adults who smoke are needed to help this population to quit cigarettes, either by switching to ENDS-only or, ideally, completely quitting all nicotine products," they added.

SOURCE

The study was led by Andrew F. Brouwer, PhD, of the Department of Epidemiology at the University of Michigan, Ann Arbor, Michigan. It was published online on September 14, 2026, in the American Journal of Preventive Medicine.

LIMITATIONS

Participants' use of other forms of tobacco and nicotine was not considered. The data grouped all individuals together without distinguishing how often they used these products in the previous month.

DISCLOSURES

The study was supported by grants from the National Cancer Institute and the FDA. One author reported receiving financial support from the National Institutes of Health National Cancer Institute.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.