Scientists analyzed a large number of studies on how marijuana affects your heart
- Scientists from Pennsylvania, New York, and California thoroughly examined dozens of studies on marijuana's impact on the heart.
- Over 1,200 people aged 20 and older participated.
Scientists reviewed more than a dozen studies about marijuana's effect on the heart, and their result is far from conclusive.
This finding contradicts a study published in August 2017, which claimed marijuana users face three times higher risk of dying from hypertension than non-users.
The August study had significant limitations, including defining users as anyone who had ever tried the drug.
The findings were alarming. But like every study, it had key limitations, including defining cannabis "users" as anyone who had ever tried marijuana. More importantly, it highlighted a significant gap in current understanding of cannabis science: How does the drug affect the heart?
Scientists simply do not know the overall impact of cannabis on cardiovascular health.
For the new study, researchers in California, Pennsylvania, and New York looked at dozens of studies about marijuana's impact on the heart. These studies examined connections between cannabis and health problems that expose people to higher heart disease risk - such as high cholesterol or high blood pressure - as well as links between marijuana and heart diseases.
But they found that all previous studies faced problems. Some examined only small numbers of people, others were too short-term, and some failed to test the right group of people, especially those most at risk under these conditions.
Scientists thus reached a disheartening conclusion: "Evidence examining marijuana's impact on cardiovascular risk factors and outcomes... is insufficient," they wrote.
This conclusion thus mocks previous studies.
What We Know About Marijuana and Heart Health
There are plenty of reasons to be concerned about cannabis and its impact on our health. Yet in many medical areas, there's insufficient comprehensive research to reach any conclusion.
Scientists know that marijuana use increases heart rate by 20 to 50 beats per minute, lasting from 20 minutes to 3 hours. This appears to potentially affect heart function, but again, more research is needed.
A recent extensive report from the National Academies of Sciences, Engineering, and Medicine found "insufficient evidence" to support or refute the idea that cannabis can increase overall heart attack risk, although some limited evidence was found suggesting drug use might be a triggering factor.
Another study, though very small, found blood pressure increases - but only when regular marijuana users stopped using the drug, not before.
This aligns with Mayo Clinic research, suggesting cannabis use could result in both blood pressure reduction and increase.
Considering this, Francesca Filbey, director of cognitive neuroscientific addiction disorders research for the Center for Brain Health, revealed to Business Insider in August that future studies should assess a broader range of factors related to cannabis use and heart health. This might include weight, BMI, and use of other substances.
How One Study Reached Such a Strong Conclusion
How is it possible that one study reached such strong conclusions about drugs and our hearts when there are so many knowledge limitations? As it turned out, numerous factors were incorrectly evaluated, including the researchers' decision to define as a "regular" marijuana user anyone who had ever tried cannabis.
Researchers selected over 1,200 people aged 20 and older for the study. Participants were previously accepted as part of a comprehensive, ongoing national health survey. One survey question concerned whether they had ever used marijuana. People who answered "yes" were classified as marijuana users; those who answered "no" were classified as non-users. Scientists processed this data and merged it with statistical mortality data from various causes obtained from the US National Center for Health Statistics.
Statistical analysis suggested that scientists assumed marijuana users had a 3.42x higher probability of dying from hypertension or high blood pressure than those who claimed never to have used cannabis. The risk also seemed to increase by a factor of 1.04 with each "additional year of use".
This is quite a stark finding. In reality, however, more than half of Americans have tried cannabis, but in this study, this half would be categorized as "regular cannabis users". According to recent surveys, only a fraction of these people use it regularly.
Source:
Brodwin, Erin. "Researchers Analyzed More than a Dozen Studies on How Marijuana Affects Your Heart - Here's What They Found." Business Insider, Business Insider, 24 Jan. 2018, www.businessinsider.com/marijuana-heart-health-research-blood-pressure-2018-1.
Author: Erin Brodwin