A new study found that using marijuana daily can affect a person’s heart by a third, compared to people who never used the drug.
A lead study author, Dr. Ishan Paranjpe, a resident physician at Stanford University, said that people who smoke marijuana are more likely to develop coronary artery disease than non-smokers.
“A growing body of evidence suggests that cannabis is not entirely without harm and may actually cause cardiovascular disease,” said Paranjpe. “Thus, the decision to use cannabis must be carefully weighed against the potential for serious heart disease.”
Coronary heart disease (CAD) is simply the blockage or narrowing of the coronary arteries, mainly caused by plaque buildup in the walls of the arteries, which supply blood to the heart and other body parts. According to the US Centers for Disease Control and Prevention, CAD is one of the most common types of heart disease. It’s also known as atherosclerosis.
Signs and Symptoms of Coronary Artery Disease
- Angina, or chest pain and discomfort, is the common symptom of CAD.
- Dizziness, feeling weak, nausea, and cold sweat.
- Experiencing shortness of breath.
- Pain or discomfort in the shoulder or arms.
CAD weakens the heart muscle over time, leading to heart failure. Heart failure is a serious condition since it means the heart cannot pump blood around the body as it’s supposed to.
Using Marijuana Once a Month or Less
The study used the All of Us Research Program to gather health information from 1 million or more people in the U.S.
Participants completed a survey on their cannabis use when enrolling in the study. The research team used the collected information to place those who responded into five categories:
- Daily users -4,726 people
- Weekly users- 2,720
- Monthly users- 2,075
- Those who used marijuana once or twice in three months- 8,749
- Those who never used the drug- 39,678
After collecting enough information, the researchers compared those categories with participants’ medical records a few years later. They factored out other potential causes of CAD, such as sex, age, and other cardiovascular risks factors like high cholesterol, alcohol consumption, type 2 diabetes, and blood pressure.
Paranjpe said in an email that the study used Mendelian randomization (MR) to determine risk, which other studies on the particular topic have yet to do.
“While other work has also linked cannabis with CAD, several potential confounders may explain this relationship. Our MR analysis suggests this relationship may be directly causal,” Paranjpe said.
Findings
- The study found that people who used marijuana only once a month or less had no significant risk.
- Daily marijuana users are 34% more likely to be diagnosed with CAD than those who have never used the drug.
How Does Marijuana Damage Heart and Blood Vessels?
Immediately after use, marijuana makes the heart beat faster and intensifies blood pressure. It may also increase the risk of stroke, heart disease, and other vascular diseases. Smoked marijuana delivers tetrahydrocannabinol (THC) and other cannabinoids into your body. These substances are harmful to the lung and cardiovascular system.
People with heart diseases who are under stress develop chest pains more quickly if they have been smoking marijuana than if they have not. This is due to the complex effects of cannabinoids on the cardiovascular system, which include making the heart pump harder, dilating blood vessels, and raising the resting heart. So, people with underlying heart disease are vulnerable to a higher risk of strokes and heart failure.
Research suggests that the risk of heart attack is many times higher after smoking marijuana than it would normally be.