Marijuana/cannabis is now becoming increasingly legalized for recreational or medicinal purposes in 28 United States and Washington, D.C. and more other states are expected to follow suit. Marijuana remains the “most commonly used illicit drug” in the U.S., according to the National Institute on Drug Abuse. However, a new medical study led by a Philadelphia cardiologist, warns of the harms of marijuana use after finding that the drug may have some negative implications for cardiovascular health.
From an analysis of more than 20 million health records of young and middle-aged patients across the U.S., researchers have revealed a connection between smoking cannabis and increased risk of stroke and heart failure. While previous marijuana research has focused mostly on pulmonary and psychiatric complications, the new study is one of only a handful to investigate cardiovascular outcomes. Researchers found that use of marijuana increased the risk of stroke by 26 percent and heart failure by 10 percent. The findings also accounted for variety of factors known to increase cardiovascular risk, such as obesity, high blood pressure, including demographic factors, health conditions and lifestyle risk behaviors like smoking and alcohol use.
Lead study author Dr Aditi Kalla, of the Einstein Medical Center in Philadelphia, PA, and colleagues said that their findings help shed to new light on how the drug can seriously affect cardiovascular health, enabling doctors to better educate patients about such risk factors.
“Like all other drugs, whether they’re prescribed or not prescribed, we want to know the effects and side effects of this drug,” said Aditi Kalla, MD, in a press release. “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.”
The study analysed over 20 million health records from the Nationwide Inpatient Sample, which includes the records of young and middle-aged patients admitted at more than 1,000 hospitals comprising about 20 percent of all U.S. health centers. The patients fell between the ages of 18 and 55 years, who were discharged from hospitals in 2009 and 2010 when medicinal or recreational marijuana use was illegal in most states. Researchers found that 316,000 patients or 1.5 percent of the group had used marijuana.
Comparing cardiovascular disease rates among those who used marijuana with those who did not use the drug, the team found marijuana use was associated with a significantly increased risk in the chain-smoking patients for stroke, heart failure, coronary artery disease and sudden cardiac death.
The people in the study who used marijuana were 26% more likely to have had a stroke at some point in their lives than those who did not use marijuana; and the people who used marijuana were also 10% more likely to have developed heart failure at some point in their lives, compared with people who did not use marijuana, the researchers found.
The researchers recently presented their results at the American College of Cardiology’s 66th Annual Scientific Session, held in Washington, D.C.
“Even when we corrected for known risk factors, we still found a higher rate of both stroke and heart failure in these patients, so that leads us to believe that there is something else going on besides just obesity or diet-related cardiovascular side effects,” explained lead researcher Dr Aditi Kalla. “More research will be needed to understand the pathophysiology behind this effect.”
Previous research has suggested that heart muscle cells have certain receptors that may be affected by use of the drug. The study in cell cultures showed that heart muscle cells have cannabis receptors relevant to contractility, or squeezing ability, suggesting that those receptors might be one way/mechanism through which drug could affect the cardiovascular system.
However, it is possible that there are other compounds that could be developed to counteract that mechanism and reduce cardiovascular risk, Dr Kalla said.
It is not clear why marijuana use would be linked to a higher risk of stroke, but previous study has suggested that marijuana use may increase the chance of blood clots, which can then lead to stroke. Further study should take a closer look at the relationship between marijuana use and heart disease, Aditi Kalla said.