Researchers find link between heavy cannabis use and heart disease
News  /  Cannabis

A large study has found that daily cannabis users were 34 percent more likely to be diagnosed with coronary artery disease than nonusers, but people who used cannabis only a few times or once a month did not have a significant risk for the disease.

The study results were reported at a Feb. 25 press briefing in Stanford, California, and were to be presented at a cardiology conference in March.

Coronary artery disease, the most common form of heart disease, occurs when blood flow to the heart is reduced by cholesterol deposits and inflammation. Symptoms include chest pain and shortness of breath, according to the Mayo Clinic.

The researchers analyzed data from 175,000 people on how often they used cannabis and their rates of heart disease. The analysis was adjusted for other factors including age, sex, body mass index, race, education, cigarette use, high blood pressure, high cholesterol and diabetes, lead researcher Dr. Ishan Paranjpe says.

Even after accounting for those risk factors, there was an association between frequent cannabis use and CAD, he says. 

“The notion that cannabis is completely benign is probably wrong, and there might be certain risk of certain cardiovascular effects of cannabis we should be more on the lookout for,” he says.


Researchers also are continuing to look at the effects of cannabis use on patients undergoing surgery. Some studies have found that cannabis can interact with drugs used before and during procedures and may result in increased postoperative pain and complications. 

In January, the American Society of Regional Anesthesia and Pain Medicine released the first-ever guidelines on cannabis and surgery, recommending that patients be screened for cannabis use before surgical procedures.

Now, a new, first-of-its-kind study puts a finer point on the relationship between cannabis and surgery.

The study by a team of anesthesiologists at Beth Israel Deaconess Medical Center in Boston, Massachusetts, found that patients who had been diagnosed with cannabis use disorder were more likely to require advanced postoperative care and had higher odds of hospital readmission, compared with cannabis users who did not have cannabis use disorder.

Cannabis use disorder is a recognized mental health disorder that is defined as a problematic pattern of cannabis use. According to a Feb. 27 report on the study at, the term in essences describes people with cannabis use disorder are unable to stop using despite problems the drug’s use might be causing.

The researchers looked at data from more than 210,000 patients who underwent noncardiac surgery between January 2018 and June 2020 and categorized them into those who had used cannabis prior to surgery, those who were nonmedical cannabis users and those who had been diagnosed with cannabis use disorder.

“The notion that cannabis is completely benign is probably wrong.”
— Dr. Ishan Paranjpe

Another finding was that cannabis users who did not have cannabis use disorder were less likely to need advanced care after surgery and had shorter hospital stays than noncannabis users.

“Our analysis revealed that cannabis use is very common and has substantially increased among patients undergoing surgery, reflecting trends in the general population; however, differential effects on postprocedural health care utilization were observed between patients with moderate non-medical cannabis use and patients with a cannabis use disorder,” the researchers conclude.

The study was published in the March 2023 issue of The Lancet’s eClinicalMedicine journal.


Marijuana legalization is associated with a reduction in the number of alcohol-related fatalities involving pedestrians, a new study finds.

The study by two researchers at Florida Polytechnic University, published Feb. 17 in the journal IATSS (International Association of Traffic and Safety Sciences) Research, looked at the relationship between marijuana legalization and rates of pedestrian-involved fatal crashes from 1985 to 2019.

Legalization of both medical and recreational cannabis was linked with overall declines in pedestrian fatalities, including alcohol-related fatalities, the authors found. They suggested these results may be due to the substitution of cannabis for alcohol.

“As of 2019, we find liberalization has been associated with lower pedestrian fatalities, not higher,” the researchers conclude. “Further, the pattern is consistent with the alcohol substitution hypothesis. Specifically, the induced decline in alcohol-related fatalities following liberalization is large enough to more than compensate for any additional fatalities due to marijuana consumption.”

Some other studies support the conclusion that marijuana is a potential substitute for alcohol, NORML writes in its report on the Florida Polytechnic study. For example, a study published in 2021 in the journal Addiction found that cannabis use was associated with a decrease.

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