Smoking marijuana increases the risk of STROKE by more than a quarter, study warns

Using marijuana can increase your chances of a stroke and heart failure, a new study has warned.

Scientists say that smoking cannabis increases the stroke by 26 percent and heart failure by 10 percent.

The drug was also linked with a variety of factors known to increase cardiovascular risk, including obesity, high blood pressure, smoking and alcohol use.

As more states look to legalize the drug, or to prescribe it medically to alleviate symptoms of other diseases, the study sheds new light on how the drug can seriously affect cardiovascular health.

Smoking marijuana can increase your risk of both a stroke and heart failure, a new study warns

Smoking marijuana can increase your risk of both a stroke and heart failure, a new study warns

The study analyzed over 20 million records of young and middle-aged patients from the Nationwide Inpatient Sample – compiled from one-fifth of all US health centers.

The patients fell between the ages of 18 and 55 and were discharged from over 1,000 hospitals in 2009 and 2010, when recreational marijuana use was illegal in every state.

Researchers found that 316,000 patients, or 1.5 percent, had marijuana use written in their charts.

Compared to patients who didn’t report cannabis use, the team found a significantly increased risk in the pot-smoking patients for stroke, heart failure, coronary artery disease and sudden cardiac death.

The drug carried a higher risk even after accounting for demographic factors, other health conditions and lifestyle risk factors such as smoking tobacco and drinking.


Twenty-eight states and the District of Columbia have legalized marijuana for a variety of medical uses.

Eight of those states, plus the nation’s capital, have also legalized the drug for recreational use.

Those states are: Colorado, California, Oregon, Washington, Maine, Nevada, Alaska and Massachusetts.

It means almost one quarter of Americans (more than 20 percent) now have access to recreational marijuana, and more than 60 percent to the medical variety.

But experts – including the White House Surgeon General Dr Vivek Gupta – warn legalization is moving faster than research.

Dr Gupta released a report in November urging caution with the drug, saying: ‘Marijuana is in fact addictive’.

He cited ‘a growing body of research’ suggesting marijuana’s chemicals can help with ‘pain, nausea, epilepsy, obesity, wasting disease, addiction, autoimmune disorders, and other conditions’.

While Dr Gupta supports easing restrictions on marijuana studies, he says this is merely to accelerate our scientific understanding of the drug -not as a green light for Americans to smoke more cannabis. 

‘Even when we corrected for known risk factors, we still found a higher rate of both stroke and heart failure in these patients, said lead author Dr Aditi Kalla, a cardiology fellow at the Einstein Medical Centre in Philadelphia.

‘So that leads us to believe that there is something else going on besides just obesity or diet-related cardiovascular side effects.

‘More research will be needed to understand the pathophysiology behind this effect.’

Cell cultures in the study showed heart muscle cells have cannabis receptors relevant to contractility, or squeezing ability.

This suggests that the receptors could be one mechanism affecting the cardiovascular system.

However, there are other compounds that could be developed to counteract that mechanism and reduce cardiovascular risk, according Dr Kalla.

She added: ‘Like all other drugs, whether they’re prescribed or not prescribed, we want to know the effects and side effects of this drug

‘It’s important for physicians to know these effects so we can better educate patients such as those who are inquiring about the safety of cannabis or even asking for a prescription for cannabis.’

Previous studies has focused on the harm caused to the lungs or the mental state by marijuana use. 

The researchers noted that because the study was based on hospital discharge records, the findings may not be reflective of the general population. 

Dr Kalla said that the growing trend toward legalization of marijuana in the US could mean that patients and doctors will become more comfortable speaking openly about marijuana use.

She says this would allow for better data collection and a better understanding into the drug’s direct effects and side effects.

One thought on “Smoking marijuana increases the risk of STROKE by more than a quarter, study warns

  1. I’m surprised doctors are still treating this as a mystery. The reason cannabis boosts risk of stroke and heart attack has everything to do with tar (and nothing to do with THC or any of the psychoactive chemicals).

    The inhalation of burning plant material, whether it’s tobacco, cannabis or any other plant, infuses the blood with all the chemicals found in the plant. The polar molecules are water soluble, so they easily flow with the blood and are eventually extracted by the liver and/or kidneys. The non-polar molecules (commonly known as tar) are not water soluble. Tar is gooey and it sticks to everything, including the inside of blood vessels, the heart, the brain and everything else it comes in contact with. The first place blood goes after the lungs is back to the heart, and after the heart, quite a bit goes through the carotids and vertebral arteries to the brain.

    Therefore, the heart and brain of every smoker gets a regular dose of gooey tar to foul things up. It’s as simple as that.

    (Incidentally, the ingestion of cannabis products will have much less effect on both the heart and the brain because the blood supply from the digestive tract is first filtered through the liver, which does a very good job at clearing non-polar molecules from the blood.)

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