American researchers have suggested that people who frequently smoke weed have a greater risk of heart attack and stroke, after their analysis of several years of surveys on increases in marijuana and cannabis consumption.
The article, published in The Journal of the American Heart Association, analysed responses to the US Government’s annual survey on behavioural risk from 2016 to 2020 in which respondents answered various questions, including reporting their own health problems related to heart disease.
About 4% of the respondents reported daily marijuana use, which the researchers suggested raised the chance of a heart attack by 25% and of a stroke by 42%. Among those who never smoked tobacco, daily use was tied to a 49% higher risk of heart attack and a more than doubled risk of stroke, the study indicated.
The New York Times reports that about three-quarters of the respondents said smoking was their main method of using weed. The other quarter consumed it by vaping, through edibles or drinking it.
“Cannabis smoke releases the same toxins and particulate matter as tobacco,” said the study’s first author, Abra Jeffers, a data analyst at Massachusetts General Hospital in Boston. She conducted the analysis during her post-doctoral fellowship at the University of California-San Francisco.
The study is merely observational in its review of survey responses; it does not provide conclusive evidence that regular marijuana use causes heart disease.
Even so, researchers and experts said they were concerned about its implications, especially as cannabis use has increased in recent years. Thirty-eight states have legalised medical use of marijuana, and 24 have begun allowing recreational use.
Dr Nora Volkow, director of the National Institute of Drug Abuse, said as cannabis consumption has risen, “there has also been an increase in the emergence of adverse health effects including addiction, respiratory problems, accidents, psychosis and cardiovascular events”.
The US Drug Enforcement Administration is weighing whether to follow the recommendations of a team of federal scientists at the Food and Drug Administration, which concluded last year that marijuana should be reclassified to a less restrictive category of controlled substances. They cited a lesser potential for abuse than other drugs have as well as marijuana’s possible medical benefits.
But the new paper’s authors warned that frequent marijuana use “could be an important, unappreciated risk factor leading to many preventable deaths”.
“This study demonstrates that smoking cannabis may be as harmful as smoking tobacco,” said Dr Salomeh Keyhani, a professor of medicine at the University of California-San Francisco, and the study’s senior author.
“Cannabis is being marketed to the public as a substance that is harmless and that might be good for you,” Keyhani added. “I worry that we’re sleepwalking into a public health crisis. The progress on tobacco smoking might be undone.”
Heart disease is already the nation’s leading cause of death. The US Centres for Disease Control and Prevention said 695 000 Americans died in 2021 of cardiovascular-related causes, like coronary artery disease.
Other surveys have documented the surge in consumption of marijuana. The percentage of Americans reporting marijuana use increased to 17% last year from 7% in 2013, according to a Gallup poll.
A study published in August and financed by the National Institute of Drug Abuse offered more details on consumption by age. From 2012 to 2022, reported use among adults up to age 30 increased to 44% from 28%, while daily use rose to 11% from 6%. Among those 35- to 50-year-olds, the proportion for overall use rose to 28% from 13%.
A 2023 federal survey documented marijuana use in the past year among 8% of eighth graders, 18% of 10th graders and 29% of 12th graders.
The new study was funded by the National Heart, Lung and Blood Institute, which is part of the National Institutes of Health. The surveys that were analysed came from 434 104 respondents, who were 18 to 74-years-old: 60% were white, 12% were black, and 19% were Hispanic.
Dr David Goff, director of a cardiovascular division at the institute that financed the research, cautioned that comparing the theoretical harms of smoking tobacco versus marijuana was challenging because of differing consumption patterns. People tend to consume more cigarettes a day, but marijuana users tend to inhale marijuana more deeply and hold it for longer.
“What we can say is it’s a bad idea to put smoke in your lungs,” he said.
Even relatively casual weed use had an association with heart disease in the new study. Weekly use was tied to a 3% greater risk of heart attack and a 5% greater chance of stroke.
Robert Page, a pharmacist at the University of Colorado School of Medicine who was not involved with the new study, said that patients and their health care providers should have open conversations about cannabis use. But he added that even doctors were often unaware of the risks.
“People don’t know the data,” he said. “They think because it’s natural, it’s safe.”
Study details
Association of cannabis use with cardiovascular outcomes among US adults
Abra Jeffers, Stanton Glantz, Amy Byers and Salomeh Keyhani
Published in the Journal of the American Heart Association on 28 February 2024
Abstract
Background
We examined the association between cannabis use and cardiovascular outcomes among the general population, among never‐tobacco smokers, and among younger individuals.
Methods and Results
This is a population‐based, cross‐sectional study of 2016 to 2020 data from the Behavioral Risk Factor Surveillance Survey from 27 American states and 2 territories. We assessed the association of cannabis use (number of days of cannabis use in the past 30 days) with self‐reported cardiovascular outcomes (coronary heart disease, myocardial infarction, stroke, and a composite measure of all 3) in multivariable regression models, adjusting for tobacco use and other characteristics in adults 18 to 74 years old. We repeated this analysis among nontobacco smokers, and among men <55 years old and women <65 years old who are at risk of premature cardiovascular disease. Among the 434 104 respondents, the prevalence of daily and nondaily cannabis use was 4% and 7.1%, respectively. The adjusted odds ratio (aOR) for the association of daily cannabis use and coronary heart disease, myocardial infarction, stroke, and the composite outcome (coronary heart disease, myocardial infarction, and stroke) was 1.16 (95% CI, 0.98–1.38), 1.25 (95% CI, 1.07–1.46), 1.42 (95% CI, 1.20–1.68), and 1.28 (95% CI, 1.13–1.44), respectively, with proportionally lower log odds for days of use between 0 and 30 days per month. Among never‐tobacco smokers, daily cannabis use was also associated with myocardial infarction (aOR, 1.49 [95% CI, 1.03–2.15]), stroke (aOR, 2.16 [95% CI, 1.43–3.25]), and the composite of coronary heart disease, myocardial infarction, and stroke (aOR, 1.77 [95% CI, 1.31–2.40]). Relationships between cannabis use and cardiovascular outcomes were similar for men <55 years old and women <65 years old.
Conclusions
Cannabis use is associated with adverse cardiovascular outcomes, with heavier use (more days per month) associated with higher odds of adverse outcomes.
See more from MedicalBrief archives:
Cannabis smokersʼ risk of deadly complication doubles after rare
Is marijuana as safe as we think?
Smoking marijuana may increase risk of lung problems