More Americans think smoking marijuana every day and secondhand exposure is safer than inhaling tobacco despite medical research showing otherwise, a study has found.
Nine researchers published the study Friday in JAMA Network Open. They surveyed 5,035 adults about their perceptions of the two substances in 2017, 2020 and 2021.
Respondents perceived daily smoking of cannabis or smoke exposure to be safer than tobacco and increasingly favored cannabis over tobacco in each succeeding survey, the study reported.
The findings show the need for further research to educate consumers as more states legalize marijuana, said Beth Cohen, a co-author of the study and professor of medicine at the University of California, San Francisco.
“It seems natural that if you see something used more often and it’s legal to purchase, you would start to perceive it as less risky,” Dr. Cohen told The Washington Times. “As cannabis industry advertising and promotion increase, people are exposed to more positive messages about cannabis, and that could contribute as well.”
More than one-third of adults surveyed said daily smoking of cannabis was safer than tobacco, with that number growing from 1,742 participants (36.7%) in 2017 to 2,107 participants (44.3%) in 2021. There was a similar increase in attitudes toward secondhand marijuana smoke, where the number of participants who found it safer than tobacco increased from 1,668 (35.1%) adults in 2017 to 1,908 (40.2%) in 2021.
Younger participants aged 18-29 and the unmarried were more likely than retired adults to move toward safer views of marijuana smoking, the study noted.
Doctors have warned that tobacco and marijuana smoke contain similar particles, carcinogens and toxins that can damage the lungs, heart and airway tissue, despite the lack of detailed research into the risks of cannabis.
“We do know from animal studies that tobacco and cannabis smoke exposure lead to similar concerning cardiovascular effects,” Dr. Cohen said. “Researchers have also analyzed hundreds of chemicals in tobacco and cannabis smoke and found they contain many of the same toxins and carcinogens.”
According to the study, existing research has linked marijuana to “multiple negative health outcomes, including cannabis dependence, increased respiratory symptoms, worse cognitive performance and increased incidence of psychiatric disorders.”
Much like alcohol, experts say smoking marijuana can impair driving, turning it into a highway safety risk. Getting “high” before getting behind the wheel slows reaction time, distorts distance perception and decreases coordination.
The study comes as marijuana smoking has increased in recent years and involves higher concentrations of tetrahydrocannabinol, or THC. THC is the psychoactive substance in cannabis that, in higher doses, can produce intense nausea and scream-vomiting or “scromiting” in users.
The average potency of marijuana plant material has jumped from 1% to 3% THC content in the 1970s to 18% to 23% today, according to Smart Approaches to Marijuana, an organization that warns about the potential harm of cannabis use.
More than 20 states have legalized recreational marijuana over the past decade, including Maryland last month and Minnesota this month.
On Thursday, Gallup reported that 50% of adults responding to a national survey say they have tried marijuana in their lifetimes, a new high in more than half a century of polling.
Gallup first surveyed the question in 1969, when just 4% said they had tried marijuana.
“As marijuana has become more available to Americans and legal in an increasing number of states, their reports of use and experimentation have increased too,” Gallup said.
Meanwhile, cigarette smoking has dropped to new lows among all but the oldest adults. But increasing numbers of young people report using electronic cigarettes, which carry similar health risks.
More than 1 in 10 young adults now use e-cigarettes in the process known as vaping, the Centers for Disease Control and Prevention reported last month.
Vaping involves using battery-operated e-cigarettes to heat a liquid solution, creating an aerosol that users inhale into their lungs.
The CDC found 11% of adults aged 18-24 reported using e-cigarettes, including 11.6% of men and 10.3% of women, making them the likeliest age group to vape. The federal agency collected the data from a national health survey in 2021, the most recent year for which figures are available.
Many vapes contain nicotine. All contain chemicals doctors have warned can be more addictive than traditional cigarettes, besides increasing the risk of heart, lung and blood vessel diseases.
Public health officials have condemned e-cigarettes in all cases except for people using them to quit cigarettes, leading public places to ban tobacco vaping.
In a July 17 statement, the American Heart Association flagged “independent health risks” in the nicotine, including the flavoring agents, sweeteners, propylene glycol and vegetable glycerol used to make e-cigarettes.
The statement noted that “e-cigarette use more than doubled from 2017 to 2019 among middle and high school students.”
Disposable vapes have appealed to younger users through a variety of sweet flavors — including watermelon, berry, mango, chocolate peppermint, sweet cream and coffee — that state and federal officials have moved to prohibit.
In 2020, the Food and Drug Administration enacted a “flavor ban” on all vapes except for menthol and tobacco-flavored products. Last year, the Supreme Court refused to halt a California law banning in-store sales of all flavored vape and tobacco products.
According to Dr. Cohen, emerging research backs up people who believe “smoke is smoke” and lobby public places to ban marijuana alongside tobacco.
“Given the similarities in the smoke, there is reason for concern,” Dr. Cohen said.
The study credited decades of “aggressive campaigns” from state and federal government officials for “dramatically reducing the prevalence of adult cigarette smoking and creating safer smoke-free environments.”
“Despite this, regulation of cannabis has tended to be less restrictive than that for tobacco, with many smoke-free laws being amended to make exclusions that allow smoking or vaping of cannabis,” the researchers noted.
A recent flood of cannabis advertising makes it harder for officials to explain the different risks of marijuana smoking, vaping and edibles, said Coleman Drake, a University of Pittsburgh public health professor who studies the impact of recreational cannabis laws.
“Tobacco is less varied in this regard,” Mr. Drake told The Times. “Cannabis use can be helpful for some people in dealing with chronic pain, but smoking it is always going to have negative cardiovascular effects.”
