Smoking Marijuana Linked to Increased Heart Attack Risk

Smoking marijuana (cannabis) more than once a month is linked to a higher risk for a heart attack before age 50, according to a new study published in the journal Cell[1].

As a growing number of U.S. states legalize marijuana for recreational use, a key question is how greater use of the drug — if it is used more widely or more frequently — will affect health outcomes. Right now, there is limited research on the subject, largely because federal law still criminalizes use of the drug[2] — and many research institutions rely on federal grants that could be in jeopardy if they are found to be in breach of the law. In fact, until 2020, U.S. research institutions could conduct studies of marijuana using plant material from only one federally authorized source — meaning they couldn’t evaluate the wide range of consumer products sold in many states.

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Still, there have been some recent studies on the health effects of marijuana, including one that looked at exposure to the drug during pregnancy. That study found that young children whose mothers used marijuana during pregnancy were more likely to have poor measures of metabolic health[4], including a higher body weight and higher blood glucose.

For the latest study, researchers looked at how various health outcomes were affected by marijuana use in people who enrolled in the UK Biobank[5], a large general research study in Britain. They compared three different groups of participants between the ages of 40 and 69, as noted in an NBC News[6] article on the study — those who reported smoking marijuana more than once a month (about 11,000 people), those who smoked marijuana less frequently (about 23,000 people), and those who didn’t smoke marijuana (about 122,000 people).

Smoking marijuana more than once a month linked to increased heart attack risk

After adjusting for participants’ age, sex, and body-mass index (BMI[7], a measure of body weight that takes height into account) — all of which are known to affect a person’s heart attack risk — the researchers found that those who smoked marijuana more than once a month were more likely to have a heart attack over the course of the study. They were also more likely to have a heart attack before age 50 — an event known as a premature heart attack, which is linked to a higher risk for future heart attacks, heart failure, and life-threatening heart rhythm disorders, according to a news release[8] on the study.

“Marijuana has a significantly adverse effect on the cardiovascular system,” said study author Mark Chandy, MD, PhD, an instructor of medicine at Stanford Medicine, in the news release. “As more states legalize marijuana use, I expect we will begin to see a rise in heart attacks and strokes in the coming years.”

On the other hand, the researchers found that a chemical called genistein — a small molecule that is derived from soy and fava beans — may be taken to effectively block the blood vessel inflammation that occurs due to smoking marijuana, while still allowing the drug to affect the brain. They noted that taking genistein may be a good solution for people who smoke marijuana for medical reasons — but there is no reason to believe it wouldn’t benefit recreational marijuana users, as well.

Want to learn more about cannabis and health? Read “CBD Oil and Diabetes.”[9]

  1. Cell:
  2. largely because federal law still criminalizes use of the drug:
  3. sign up for our free newsletters:
  4. were more likely to have poor measures of metabolic health:
  5. UK Biobank:
  6. NBC News:
  7. body-mass index (BMI:
  8. news release:
  9. “CBD Oil and Diabetes.”:

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