Marijuana use linked with increased risk of heart failure and heart attack: New studies

Two new studies exploring the long-term effects of marijuana have found a possible link between use of the drug and one’s risk for major health events like heart failure and heart attack.

In the non-published research to be presented at the American Heart Association Scientific Sessions in Philadelphia, one study found that daily use of marijuana raised the risk of heart failure by 34% compared to people who reported never using it.

The other study used a nationwide database of hospitalizations to examine how older marijuana users were affected by cardiovascular events during hospital stays compared to non-marijuana users. The research found that older people with existing conditions of Type 2 diabetes, high blood pressure and high cholesterol had a significantly higher risk for a major acute heart or brain event if they reported marijuana use.

The studies sought to explore the implications of frequent and long-term cannabis use, as there is currently little research on the topic despite an increase in regular users brought on by legalization in many states.

“Prior research shows links between marijuana use and cardiovascular disease like coronary artery disease, heart failure and atrial fibrillation, which is known to cause heart failure,” said Yakubu Bene-Alhasan, M.D., M.P.H., lead author of the first study conducted via a National Institutes of Health sponsored research program called “All of Us.”

“Marijuana use isn’t without its health concerns, and our study provides more data linking its use to cardiovascular conditions,” he said in a statement.

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Daily marijuana use increases risk of heart failure nearly one-third: Study

The first study, performed through the NIH “All of Us” research program, followed 156,999 patients over the course of just under four years.

The participants self-reported non-medicinal use of marijuana regularly through surveys from 2016 to 2022. Each individual was monitored for no more than 45 months after enrolling in the program. The median age of participants was 54.

Researchers found that 2,958 people, or almost 2%, developed heart failure during the study.

Overall, daily cannabis use was associated with a 34% increased risk of heart failure, regardless of age, sex at birth or smoking history, the data found. However, the study did not specify how the marijuana was consumed, something researchers think could have an impact on cardiovascular outcomes.

“Our results should encourage more researchers to study the use of marijuana to better understand its health implications, especially on cardiovascular risk,” Bene-Alhasan said.

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Older marijuana users with existing conditions saw 20% higher rate of major heart or brain events: Study

In the second study, another set of researchers analyzed data from the 2019 National Inpatient Sample, the largest nationwide database of hospitalizations in the U.S.

Using a population of non-tobacco users over the age of 65 with cardiovascular risk factors, they split the group into non-marijuana users and marijuana users based on hospital records. The population was examined for marijuana users who suffered cardiovascular events like heart attack, stroke, cardiac arrest or arrhythmia during their hospital stay.

Of the 28,535 older adult cannabis users with existing conditions like high blood pressure, high cholesterol or diabetes, 20% were at increased risk of having a major heart or brain event while hospitalized compared to those not using cannabis. 

Cannabis users had a 1.6% higher rate of heart attacks than non-users.

The large-scale nature of the analysis and the fact it relies on hospital-specific coding, however, did pose limitations to the study, said researchers.

“Since 2015, cannabis use in the U.S. has almost doubled, and it is increasing in older adults, therefore, understanding the potential increased cardiovascular risk from cannabis use is important,” said lead study author Avilash Mondal, M.D., a resident physician at Nazareth Hospital in Philadelphia in a statement.

Bottom line

It’s important to keep in mind that neither study has been published or peer-reviewed yet, and existing literature on the subject is relativity sparse. However, researchers have suggested the medical community continue to pursue the topic based on these findings.

“The latest research about cannabis use indicates that smoking and inhaling cannabis increases concentrations of blood carboxyhemoglobin (carbon monoxide, a poisonous gas), tar (partly burned combustible matter) similar to the effects of inhaling a tobacco cigarette, both of which have been linked to heart muscle disease, chest pain, heart rhythm disturbances, heart attacks and other serious conditions,” said Robert L. Page II, Pharm.D., M.S.P.H., FAHA.