Study finds shift away from cigarettes could reshape future cancer burden

As cigarette smoking reaches historic lows in the U.S., new research from MUSC Hollings Cancer Center suggests a fundamental shift in tobacco use is driving that trend. Younger adults are increasingly switching to non-combustible nicotine products, particularly electronic cigarettes, also known as e-cigarettes.

The findings, published in JNCI Cancer Spectrum, offer new insight into how tobacco use is evolving and what those changes could mean for rates of tobacco-related cancers. Because combustible tobacco products, mainly cigarettes, are responsible for a large majority of cancer deaths, understanding what types of tobacco products people use – and not simply whether they use tobacco – is becoming increasingly important for predicting the future burden of tobacco-related cancer.

"This study peels back another layer of the onion," said tobacco control researcher K. Michael Cummings, Ph.D., the study's lead author. "We wanted to understand how tobacco use patterns were changing. Our results show that exclusive cigarette use is being replaced by exclusive use of other products, mainly e-cigarettes, especially among young adults.”

A closer look at tobacco use

National surveys reveal that cigarette smoking prevalence is under 2% among youth and is declining steadily among adults. The decline in smoking appears to have accelerated in recent years, even though overall tobacco use has remained relatively stable. That raises an important question: If fewer people are smoking cigarettes, what are they using instead?

That question builds on years of research by Cummings and Hollings colleagues examining the health effects of switching from combustible cigarettes to electronic cigarettes. Their previous studies showed that smokers who switch to electronic cigarettes are exposed to far fewer cancer-causing chemicals and are more likely to quit smoking than those who continue using cigarettes.

To look at those patterns at the population level, the researchers in this study analyzed data from the National Health Interview Survey, a nationally representative survey of U.S. adults, covering the years 2015 through 2023. Unlike previous national reports that tracked overall tobacco use, this study distinguished between combustible products, including cigarettes, cigars, pipes and hookahs; noncombustible products, including electronic cigarettes, smokeless tobacco and nicotine pouches; and dual use of both product types.

The red light, or take-home message, for me is that we're failing older people who smoke cigarettes. These are people with decades of smoking behind them, and they're not changing to lower-risk noncombustible tobacco products as much as younger adults. They're the group that stands to gain the most immediate health benefits from the elimination of smoked tobacco.

“We selected 2015 as the starting point because that is when electronic cigarettes started to gain popularity,” explained Cummings.

The study combined expertise in tobacco control, behavioral science and population modeling. Hollings investigators Avery Roberson and Tracy Smith, Ph.D., contributed to the study alongside collaborators from Rutgers University, Georgetown University, University of Michigan and University of British Columbia.

The analyses showed that exclusive combustible tobacco use declined across nearly every age group, with the steepest declines for young adults 18 to 34 years. During the same period, the exclusive use of noncombustible products increased, driven largely by electronic cigarettes. Dual use of both product types was uncommon, reported by only 2% to 3% of adults.

"One of the most surprising findings was that dual use wasn't increasing," Cummings said. "There’s this expectation that as cigarette smoking declines, it would be because more people are using both cigarettes and e-cigarettes. Instead, dual use stayed remarkably stable while exclusive use of e-cigarettes increased."

The trends also revealed an important divide by age. While younger adults increasingly moved away from combustible tobacco, adults 55 years and older continued to smoke cigarettes, with lower uptake of noncombustible tobacco products.

"The red light, or take-home message, for me is that we're failing older people who smoke cigarettes," Cummings said. "These are people with decades of smoking behind them, and they're not changing to lower-risk noncombustible tobacco products as much as younger adults. They're the group that stands to gain the most immediate health benefits from the elimination of smoked tobacco.”

A population shift with long-term implications

Those changing patterns prompted a broader question: Is tobacco use becoming less harmful at the population level?

To understand the tobacco landscape more completely, the researchers developed a population harm-reduction index. Rather than simply measuring overall tobacco use, the new index compares the prevalence of exclusive noncombustible tobacco use with the prevalence of any combustible tobacco use. As the ratio increases, it suggests that more people are replacing products that burn tobacco with alternatives that expose them to substantially fewer cancer-causing chemicals.

The strongest evidence of that shift was seen among adults ages 18 to 24, for whom exclusive noncombustible tobacco use was greater than use of any combustible tobacco.

"If you believe, as the scientific evidence increasingly suggests, that noncombustible nicotine products expose people to substantially fewer cancer-causing chemicals than combustible tobacco, then this index gives us a way to measure whether that substitution is happening at the population level," Cummings said. "Among young adults, we're seeing exclusive noncombustible use rapidly replacing combustible tobacco use, which is a positive population health trend."

Because combustible tobacco products are responsible for nearly a third of cancer deaths and 90% of lung cancer deaths, the recent shift away from cigarettes will reshape the nation's future cancer burden – although the full impact will not be visible for decades, researchers say.

Cummings emphasized that no tobacco or nicotine product is completely safe: The healthiest choice is never to begin using tobacco or nicotine or to stop using those products entirely. But he said studies like this highlight the importance of looking beyond overall tobacco use to understand how use is changing and what those shifts mean for future generations.

"As cigarette smoking continues to decline, it's important to understand what is replacing it. If younger adults continue moving away from combustible tobacco, we should be looking at substantially fewer smoking-related cancers several decades from now."

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