Study on Marijuana and Heart Health Stirs Debate

Researchers say long-term marijuana use can increase the risk of hypertension, but cannabis advocates say this particular study is faulty.

When it comes to heart health, is marijuana any safer for you than tobacco?
A new study published today in the European Journal of Preventive Cardiology concluded that marijuana use is associated with a threefold risk of death from hypertension.

“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,” said Barbara A. Yankey, study lead author, and PhD student in the School of Public Health at Georgia State University, in a press statement.
Their results were based on a specially designed retrospective study.
Researchers analyzed data from 1,213 participants who were considered marijuana users based on their responses to the 2005-2006 National Health and Nutrition Examination Survey (NHANES).
This data was cross referenced with mortality data from 2011 from the National Center for Health Statistics.
“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,” said Yankey. “We found higher estimated cardiovascular risks associated with marijuana use than cigarette smoking.”

Advocates question study results

Marijuana advocates are skeptical of the research.

Paul Armentano, the deputy director of the National Organization for Reform of Marijuana Laws (NORML), not only disputes the results of the study, but the methodology of it as well.
Researchers explain that their “retrospective study” was utilized due to the lack of longitudinal studies on the long-term cardiovascular effects of marijuana use — something Armentano says is patently false.
In his response to Healthline, Armentano pointed out two separate longitudinal studies that examined the relationship between marijuana use and some common cardiovascular ailments.
The first, published this year, followed more than 5,000 individuals for 25 years, beginning in the mid-1980s.
“Compared with no marijuana use, cumulative lifetime and recent marijuana use showed no association with incident CVD [cardiovascular disease], stroke, or transient ischemic attacks, coronary heart disease, or CVD mortality,” the authors of that study wrote.
Another longitudinal study from last year involving 1,037 individuals who were followed for 38 years came to a similar conclusion.
“We found no association between cannabis and cardiovascular risks [e.g., high blood pressure, higher cholesterol], which may appear at odds with evidence that cannabis use increases risk for cardiovascular complications,” the authors wrote.
Armentano also argued that this new study’s results are also jeopardized because of the ambiguous definition of “marijuana user.”
The only qualification to meet this definition was if NHANES respondents answered “yes” when asked if they had ever used marijuana. The study did not ascertain frequency of use, or if a respondent even continued to use marijuana at all through the documented time period.

Some cautions

Armentano acknowledged that cannabinoids (a class of chemicals found in marijuana, — the most well-known is THC, a psychoactive) do affect blood pressure — a subject that he has written about previously.
Other studies have also linked smoking marijuana to heart attack risk, stating it is a “rare trigger of myocardial infarction.”
Armentano cautioned that, “Potential high-risk populations may wish to refrain from cannabis inhalation because of these concerns.”