Dr. Michael Weaver, medical director of the Center for Neurobehavioral Research on Addiction at the University of Texas Health Science Center at Houston, said the study’s finding of an association between cannabis use disorder and cardiovascular events is plausible.
Weaver is shown with Dr. Erin Andrews, a second-year child and adolescent psychiatry fellow. Photo courtesy of the University of Texas Health Science Center at Houston
NEW YORK, Sept. 28 (UPI) -- Adults with cannabis use disorder appear to have a roughly 60% higher risk of a first heart attack, stroke or other major cardiovascular event than comparable individuals without this addiction, a new Canadian study suggests.
The study, published Thursday in the journal Addiction, evaluated an association between problematic marijuana use and the initial occurrence of adverse cardiovascular disease events such as heart attack, stroke, cardiac dysrhythmias and peripheral vascular disease.
Cannabis use disorder is a recognized medical and psychiatric condition characterized by problematic and often compulsive use of cannabis, or marijuana, despite negative consequences on physical, mental or social well-being.
Tapping into five Canadian health databases, the investigators engaged almost 60,000 participants and followed them from January 2012 to December 2019.
Half of the participants had a diagnosis of cannabis use disorder, while half did not, and the groups were matched by gender, year of birth and time of presentation to the health system. The investigators excluded people with previous adverse cardiovascular disease events.
Of those with cannabis use disorder, 2.4%, or 721, experienced a first-time cardiovascular disease event, compared with 1.5%, or 458, in the nonusers group.
Among people with cannabis use disorder, those with no co-occurring medical illness, no prescriptions and fewer than five visits to health services in the last six months had an even higher risk of a first-time cardiovascular disease event -- about 1.4 times greater than the rest of this group.
Perception of health
The researchers speculated that this may be because those people perceived themselves to be healthy and may not have heeded or even noticed warning signs of an imminent heart attack, stroke or other major cardiovascular event.
Dr. Anees Bahji, lead author of the study, told UPI via email that "the researchers aimed to address an important gap in our understanding of the health implications of cannabis use disorder, particularly its impact on cardiovascular health."
Bahji is a doctoral student and a clinical assistant professor in the departments of community health sciences and psychiatry at the University of Calgary's Cumming School of Medicine in Calgary, Alberta, Canada.
"As cannabis use has become more prevalent in various parts of the world, including Canada, it's crucial to explore and quantify potential risks associated with its use," he said.
The information gleaned from the study "can be useful for both healthcare providers and individuals who use cannabis," particularly in regions where it is legal and easily accessible, Bahji said. "Overall, these findings may also inform public health initiatives and policies related to cannabis use."
Additional research is necessary to understand the underlying mechanisms completely and to confirm the study's findings. Not only can individual responses to cannabis vary widely, but various factors, such as the method of consumption and other health conditions, also can play a role in the observed associations, he said.
"Individuals who use cannabis or are considering its use should be aware of potential health risks and consult with healthcare professionals, especially if they have pre-existing cardiovascular conditions or other health concerns," he said.
Dr. Michael Weaver, an addiction medical specialist not involved in the study, told UPI in a telephone interview that the study's finding of an association between cannabis use disorder and cardiovascular events is plausible.
Weaver is a professor in the department of psychiatry and medical director of the Center for Neurobehavioral Research on Addiction at The University of Texas Health Science Center at Houston.
"It makes sense in that we know that cannabis has effects on the cardiovascular system," he said. "People get red eyes when they smoke marijuana because it causes the blood vessels to dilate. The heart speeds up and responds to that."
Even though the difference in the number of cardiovascular events between cannabis users and nonusers was "not gigantic" in the study, "it is evidence that there are clear risks associated with cannabis," Weaver said.
Dr. Jeffrey Anderson, also not involved in the study, told UPI via email that the research is significant and well-executed. Anderson is professor of medicine (cardiology) and director of the Advanced Lipid and Prevention Clinic at Intermountain Medical Center at the University of Utah School of Medicine.
"Because cannabis has been illegal until recent years, there is little evidence for whether or how much its use can impact cardiovascular risk," he said.
"This study importantly contributes to filling that gap and indicates an important association of cardiovascular disease with cannabis use disorder, which represents an important health care issue."
Dr. Evan F. Shalen told UPI via email that "the results here are important but unsurprising." Shalen is an assistant professor of medicine in the division of cardiology at Oregon Health and Science University's Knight Cardiovascular Institute in Portland.
"People with substance use disorders are known to be at higher risk for many other conditions, including cardiovascular disease. Some of this is likely related to underlying social, economic or medical conditions that contribute both to the substance use disorder and cardiovascular disease," he said.
"This paper looks at a small segment of the population of people who use cannabis, most likely the people who use the most cannabis, and suggests that they too have a significantly increased relative risk of cardiovascular events, though it should be noted that the increased absolute risk of 0.9% is modest."
Dr. Khaled Abdul-Nour, who was not involved in the study, told UPI via email that the study "has many deficiencies and limitations" but doesn't consider the results to be significant enough "to provide firm conclusions on whether cannabis alone negatively affects cardiovascular health."
Abdul-Nour is a preventive cardiologist and chronic coronary artery disease expert at Henry Ford Health in Detroit.
"In my practice, I commonly see cannabis-consuming individuals with acute or chronic cardiovascular conditions," he said. "However, the cannabis use is confounded by other factors such as smoking, drug use and health illiteracy, all of which are more important determinants of heart disease."