New research found that 2.3% of reported marijuana users also have some form of cardiovascular disease.
The study appeared in the Journal of the American College of Cardiology.
The paper also looked at the possible interactions marijuana may have with drugs typically prescribed for cardiovascular issues, and the way marijuana chemicals may affect the heart at a molecular level.
According to the Centres for Disease Control and Prevention (CDC), heart disease — a type of cardiovascular disease (CVD) — is the leading cause of death in the United States.
In 2015, heart disease caused 23.4 % of all deaths in the U.S.
According to the American Heart Association (AHA), nearly half of all U.S. adults have some form of CVD. They cite an article in the journal Circulation that sets this figure at 121.5 million U.S. adults, which is approximately 48% of the population.
In contrast, the reported 2.3% of reported marijuana users who also have CVD is relatively low compared to the broader U.S. population.
This does not mean that marijuana use and CVD have no links. However, there is insufficient evidence to prove any connection, and what is available is of poor quality.
In the U.S., there are significant restrictions on researching marijuana. This means that scientists cannot carry out randomized clinical trials to understand its effects on health.
Researchers typically focus their research on observational studies, and the authors of the study claim that these show a possible link between marijuana use and cardiovascular events.
However, according to an article in the journal Annals of Internal Medicine, observational studies that have taken place are either inconclusive or have problems with their methodologies. This means that it is difficult for scientists to draw any conclusions from them.
The authors of the article in the Journal of the American College of Cardiology looked at data from the National Health and Nutrition Examination Survey (NHANES) to estimate how many marijuana users have CVD.
They found that 2 million of the 89.6 million U.S. adults who reported using marijuana also had CVD. This equates to 2.3% of reported marijuana users.
Dr. Ersilia M. DeFilippis, a former internal medicine resident at Brigham and Women’s Hospital, Boston, MA, is the lead author. She is now a cardiology fellow at Columbia University Irving Medical Center.
She says, “Marijuana use, both recreational and medical, is increasing nationally, yet many of its cardiovascular effects remain poorly understood. In our NHANES query, we estimated that 2 million adults with marijuana use had CVD in 2015–2016.”
“Since that time, additional states have passed legislature related to marijuana, so its use may have increased even further.”
“Notably, many of our cardiology patients are on medications that can interact with marijuana in unpredictable ways, depending on the formulation. This highlights that we need more data so that we can better counsel providers as well as patients.”
Given the increase in marijuana use in the U.S., the authors of the study urge doctors to ask patients whether they use marijuana and to review their medication if necessary.
Current evidence is limited, and what little there is does not suggest a clear link between marijuana use and cardiovascular events. Researchers need to do more high quality research to determine precisely how and why marijuana affects cardiovascular health — if it does at all.
According to the corresponding author Dr. Muthiah Vaduganathan, who is a cardiologist at Brigham, “In the clinic, patients often ask us about the safety of marijuana use, and we’re pressed to offer the best scientific evidence.”
“Our current approach is that patients who are at high risk of cardiovascular events should be counseled to avoid or at least minimize marijuana use and that rigorous scientific research should be conducted to further inform recommendations for patient care.”
– Dr. Muthiah Vaduganathan