• Posted August 14, 2023

More Americans Than Ever Believe Marijuana Smoke Is Safer Than Cigarette Smoke. They're Wrong

As cannabis use has become legal in many U.S. states for medical or recreational use, Americans' views on the drug may have gotten rosier.

In fact, a new report finds that over 44% of adults now believe smoking weed each day is safer than inhaling tobacco smoke.

That perception is counter to the science, however, and could have a serious impact on public health.

"The research that has been coming out is actually suggestive that there's a lot of overlap in terms of the toxins and carcinogens that are in [both] cannabis and tobacco smoke,"noted study author Dr. Beth Cohen, a professor of medicine at the University of California, San Francisco School of Medicine. "What we've learned in the past few years seems more concerning, not less concerning."

For this study involving more than 5,000 adults, researchers focused on public perceptions of smoking the two substances, using data from 2017 to 2021.

Many of those surveyed felt daily cannabis smoking was safer than smoking tobacco every day. While about 37% thought it was safer in 2017, that grew to 44% by 2021.

The researchers saw a similar pattern for secondhand smoke, with 35% considering secondhand cannabis smoke as safer than tobacco smoke in 2017, compared to 40% in 2021.

The reality is that smoke of any kind isn't good for your lungs, the study authors stressed.

"I feel like one of the misconceptions is that, well, cigarettes are bad for you because there's all these chemicals in them, and that's absolutely true. That's part of why they're bad for you. But really a huge piece of the harm from cigarettes is simply that they are a material that is being combusted and you're inhaling that smoke,"Cohen explained.

The particulate matter that smoke creates can get deep into the lungs, Cohen said.

While the study didn't ask people why they had these perceptions, the researchers have some theories.

One is that tobacco smoke has been studied for much longer than cannabis smoke has, and there has been a large public health effort to educate people about the dangers of tobacco. There just isn't the same amount of data about cannabis, in part because it's still illegal federally, making research a challenge.

Cannabis is currently legal for medical use in 38 states and recreationally in 23 states, along with two territories and Washington, D.C., according to the National Conference of State Legislatures.

Meanwhile, as tobacco has been increasingly restricted, with states or local governments limiting where a person can smoke, cannabis has been increasingly legalized.

That there may be some health benefits in using cannabis in certain forms makes the issue more gray than with tobacco, she added.

"I think that because of all those reasons, it didn't surprise me that more people favored cannabis over tobacco. I think it did surprise me that that perception was increasing over time, that compared to tobacco, increasingly people were selecting cannabis smoke as safer. And again, we're talking about just smoke,"Cohen said.

The study also found that people who were young, 18 to 29, were more likely to move toward the view that cannabis was safer compared to those surveyed who were aged 60 or older. Being unmarried was also more aligned with a view that cannabis was safer. Those who were retired were less likely to move toward a view of cannabis being safer than those who were working.

The findings were published online Aug. 11 in JAMA Network Open.

Dr. Albert Rizzo, chief medical officer for the American Lung Association, said he thinks there's a reason perception varies by age.

"I think in my mind the main reason is that it is becoming much more freely used by younger people who feel that it's a part of what their generation can do. But, also, I think the fact that it's being legalized more is another reason,"Rizzo said. "And I think people have to realize, just because it's legal doesn't mean it's safe. It's not being made legal for safety reasons. It's being made that way because of people's preferences and judgments."

Rizzo also noted the dangers of inhaling anything that causes inflammation in the airways.

"We don't have the long-term studies to show the effects of COPD [chronic obstructive pulmonary disease] or cancer, but our concerns are that it's very similar in the way that it took years for us to figure out that tobacco led to, with definite science, led to things like cancer and development of COPD,"Rizzo added.

The findings point to the need for more education about the impact of smoking cannabis.

"Public health agencies like the American Lung Association need to double down on education and awareness efforts about what the potential problems are with cannabis smoking,"Rizzo said.

This might mean aiming messaging at young people and their parents.

It will also be important to make it easier to study cannabis smoking, Cohen said.

Despite some limitations on the ability to research cannabis use, Cohen referenced a variety of studies in animals that showed damage from both cannabis and tobacco smoke.

One study in rats from 2016 found similar adverse cardiovascular effects from both marijuana and tobacco. Another report, published in January 2023, found these animals had increased vulnerability to heart arrhythmia from both types of exposure.

"But I do think with what we have currently, we certainly have enough to be concerned and to say that this is definitely not harmless and there is a risk," Cohen said. "And I think that's what we need to convey to people. Adults can make choices about their health and health behaviors. We just want them to make informed choices."

More information

Here's more on the health effects of marijuana.

SOURCES: Beth Cohen, MD, MAS, professor, medicine, University of California, San Francisco School of Medicine; Albert Rizzo, MD, chief medical officer, American Lung Association; JAMA Network Open, Aug. 11, 2023, online