By Aria Bendix -
NBC News
Smoking marijuana at least once a month is associated with an increased risk of heart attack, according to a new study of nearly 160,000 people in the UK.
The research, published Friday in the journal Cell, looked at more than 11,000 people between the ages of 40 and 69 who said they smoke marijuana at least once a month.
The scientists then compared that group to 122,000 other people in the same age group who didn't smoke marijuana at all, and nearly 23,000 more who smoked less often.
The study authors took into account age, gender and body mass index, three factors that influence heart disease risk, and found that frequent marijuana smokers were
more likely than nonsmokers to have a first heart attack before the age of 50.
[The UN removes cannabis from the list of most dangerous drugs and recognizes important medicinal properties]
Having a heart attack increases your risk of having others, or of developing heart failure.
These findings are in line with other similar research.
The Centers for Disease Control and Prevention warn that smoking marijuana could increase the risk of heart disease, and a 2021 study identified a link between heart attacks and marijuana use in young adults.
What effect does marijuana have on the heart?
But the new study went a step further, also seeking to discover why smoking marijuana can cause heart problems.
To investigate, the authors studied how THC affects both human stem cells and mouse stem cells.
Cases of children accidentally consuming marijuana candy are on the rise
April 21, 202202:02
It is known that when people smoke marijuana, the THC attaches to a receptor in the brain, which produces the feeling of being high.
In laboratory studies, the researchers found that THC also binds to this receptor in blood vessels.
Therefore, the researchers suggest that frequent THC use could activate that receptor in a way that causes inflammation in the blood vessels, which in turn can accelerate the buildup of plaque in the arteries, leading to a heart attack.
[Marijuana is now legal in four more US states]
“The public has a misperception, in my opinion, that marijuana is completely safe and healthy.
But actually, this study shows that
a high dose of THC, the main component of marijuana, causes vascular inflammation,
” said Joseph.
Wu, lead author of the study and director of the Stanford Cardiovascular Institute.
In any case, that part of the research did not focus on people, so the results are mainly an open door for further investigation and do not have direct implications for human health.
Wu said that human studies could offer more insight into whether THC is directly linked to heart disease.
Cannabis use in the United States
Cannabis use has become increasingly prevalent in the United States over the past decade.
In 2020, about 18% of Americans over the age of 12 reported using marijuana in the past year, compared to 7% in 2010.
Immigrants in New Mexico are recommended not to use marijuana even if the law allows it
April 2, 202200:19
Wu said that the legalization of marijuana in many states has likely influenced this trend.
Many people may also feel more comfortable admitting to using marijuana as the drug becomes more culturally accepted.
Additionally, Wu said, the legalization of cannabis has led to marijuana cigarettes becoming more potent, with higher levels of THC.
“In the old days, a joint was like 5% THC,” he said.
"Right now, some of the vendors offer joints that are 85% THC."
[Los Angeles eliminates convictions for marijuana and thousands of Latino migrants breathe easier]
The dose of THC may influence the risk of heart disease, Wu thinks.
“As more states legalize marijuana, and as growers and suppliers continue to put marijuana with more potent ingredients on the market, in my opinion, incidents of cardiovascular disease will increase,” he said.
Wu added that he would expect the same risks from smoking marijuana and consuming edibles that contain it.
Health benefits
However, that doesn't necessarily mean that marijuana lacks health benefits.
Mexican photographer prints photos on marijuana leaves and his art is exhibited in museums
March 1, 202200:24
Early research indicates that other compounds in marijuana, such as CBD, may have anti-inflammatory properties that could help with chronic pain, although more data is needed.
“We would have to do additional studies to show that CBD has anti-inflammatory effects,” Wu said.
“But we don't think THC is anti-inflammatory.
We think it's pro-inflammatory."