Issue: November 2017
November 08, 2017
3 min read

Greater awareness, education needed on CV effects of marijuana use

Issue: November 2017
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For years, little was known about the CV effects of recreational marijuana use, but recent data have emerged suggesting that, whatever its health benefits may be in other areas, marijuana may have negative effects on the heart.

The issue has become one to watch for cardiologists, as recreational marijuana use is now legal in certain U.S. states, and decriminalized in others.

“More and more states are legalizing marijuana for medicinal and recreational use,” Robert A. Kloner, MD, PhD, interim chief science officer, director of the HMRI Cardiovascular Research Institute and vice president of translation at Huntington Medical Research Institutes, Pasadena, California, and professor of medicine at University of Southern California Keck School of Medicine, told Cardiology Today. “There is a perception that the use of marijuana is perfectly safe. However, there have been a number of reports linking marijuana use to acute MI and stroke. Practitioners must be made aware of these links and be cautious in their prescriptions of medical marijuana, especially if there are already underlying heart disease and/or risk factors for heart disease. In addition, if a patient presents with HF or stroke, it is important to think about asking about marijuana use.”

Robert A. Kloner, MD, PhD
Robert A. Kloner

Recreational use of marijuana has been linked to a threefold risk for hypertensive death, according to data published in the European Journal of Preventive Cardiology.

Recent marijuana legislation in the U.S. has made it necessary to determine the association between marijuana use and CV mortality, according to Barbara A. Yankey, PhD, MPH, MPA, MSc Clin Pharm, from the division of epidemiology and biostatistics at the School of Public Health at Georgia State University, and colleagues.

“Steps are being taken toward legalization and decriminalization of marijuana in the United States, and rates of recreational marijuana use may increase substantially as a result,” Yankey said in a press release from the European Society of Cardiology. “However, there is little research on the impact of marijuana use on [cardiovascular] and cerebrovascular mortality.”

Researchers enrolled 1,213 National Health and Nutrition Examination Survey participants aged at least 20 years in a retrospective study who answered “yes” or “no” questions on the recreational use of marijuana.

Those who answered “yes” were classified by researchers as marijuana users and duration of use was determined by subtracting age at marijuana use initiation from the age at the screen in 2005.

Yankey and colleagues estimated HRs for hypertension, heart disease and cerebrovascular mortality as a result of marijuana use by conducting Cox proportional hazard regression analyses.


The researchers also controlled for cigarette use, age, race/ethnicity, alcohol use, diagnosis of hypertension and other relevant variables.

At the time of follow-up (19,569 person-years), 72.5% of the eligible participants were presumed to be alive. After adjustments, marijuana users had an increased risk for death from hypertension (HR = 3.42; 95% CI, 1.2-9.79) compared with nonusers. For each year of marijuana use, the HR was 1.04 (95% CI, 1-1.07).

“We found that marijuana users had a greater than threefold risk of death from hypertension and the risk increased with each additional year of use,” Yankey said in the release. “Our results suggest a possible risk of hypertension mortality from marijuana use. This is not surprising since marijuana is known to have a number of effects on the [cardiovascular] system. Marijuana stimulates the sympathetic nervous system, leading to increases in heart rate, [blood pressure] and oxygen demand. Emergency rooms have reported cases of angina and [myocardial infarctions] after marijuana use.”

Aditi Kalla, MD, cardiology fellow at Einstein Medical Center in Philadelphia, and colleagues collected 2009-2010 data from the National Inpatient Sample database, when legalization of marijuana was less common. The researchers focused on participants aged 18 to 55 years who reported using marijuana (n = 316,397 [1.5%]; mean age: 33 years; 60% men) or reported no use (n = 20,499,215 [98.5%]; mean age: 26 years; 38% men).

Compared with no use, those who reported using marijuana were more likely to have CV events including HF (1.4% vs. 1.2%; P < .01), stroke (1.03% vs. 0.62%; P < .0001), sudden cardiac death (0.21% vs. 0.17%; P = .02) and CAD (5% vs. 4.6%; P < .0001), according to the findings.

After adjustment for sex, age, diabetes, hypertension, CAD, hyperlipidemia, and tobacco and alcohol use, marijuana was an independent predictor of HF (OR = 1.1; 95% CI, 1.02-1.18) and cerebrovascular accidents (OR = 1.26; 95% CI, 1.16-1.36).

“Consumers also need to be educated about the potential harmful effects marijuana use may have on the CV and cerebral systems,” Kloner told Cardiology Today. “Most consumers are not aware of the findings of this and other studies. More research is needed into the effects of marijuana on the heart, brain and vasculature.” – by Darlene Dobkowski and Dave Quaile


Kalla A, et al. Abstract 1187-055. Presented at: American College of Cardiology Scientific Session; March 17-19, 2017; Washington, D.C.

Yankey BA, et al. Eur J Prev Cardiol. 2017;doi:10.1177/2047487317723212.

Disclosures: Kalla, Kloner and Yankey report no relevant financial disclosures.