Scientists from Stanford Medicine found that people who use marijuana have an increased risk of heart disease and heart attack.
They also showed that the psychoactive component of the drug, known as THC, causes inflammation in endothelial cells that line the interior of blood vessels, as well as atherosclerosis (thickening or hardening of the arteries).
The research is published in Cell and was conducted by Joseph W et al.
In the study, the team analyzed the genetic and medical data of about 500,000 people ages 40–69. The data was from the UK Biobank.
Nearly 35,000 participants reported smoking cannabis; of those, about 11,000 smoked more than once a month.
The more-than-monthly smokers were much more likely than others in the study to have a heart attack after controlling for other factors including age, body mass index, and sex.
The researchers found that frequent marijuana smokers were also more likely than nonusers to have their first heart attack before the age of 50.
This is an unusual medical event called a premature heart attack that increases a person’s lifelong risk of subsequent heart attack, heart failure, and life-threatening arrhythmias that can cause sudden death.
Inflammation of the blood vessels is a primary hallmark of atherosclerosis—the thickening of the vessel wall due to the buildup of plaques made up of fats, cholesterol, and other substances—which can lead to a heart attack.
The researchers found that the levels of inflammatory molecules in the blood of volunteers who smoked marijuana cigarettes increased significantly over the subsequent three hours.
They further showed that THC promotes inflammation and hallmarks of atherosclerosis in human endothelial cells grown in the laboratory.
Finally, laboratory mice bred to have high cholesterol levels and fed a high-fat diet developed much larger atherosclerosis plaques when injected with THC at levels comparable to smoking one marijuana cigarette per day than did control animals.
The team also found that inflammation and atherosclerosis can be blocked by a small molecule called genistein that occurs naturally in soy and fava beans.
They say genistein works quite well to mitigate marijuana-induced damage to the endothelial vessels without blocking the effects marijuana has on the central nervous system, and it could be a way for medical marijuana users to protect themselves from heart issues.
Marijuana has a significantly adverse effect on the cardiovascular system. As more states legalize marijuana use, the researchers expect we will begin to see a rise in heart attacks and strokes in the coming years.
If you care about cannabis, please read studies that cannabis could reduce blood pressure in older people, and doctors need to screen over-50s for cannabis use.
For more information about heart health, please see recent studies about a big cause of heart failure, and results showing scientists find a new way to repair human heart.
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