AHA: Marijuana may be harmful to heart and blood vessels, needs more study


A new report from the American Heart Association found that marijuana not only has no cardiovascular benefits but may be harmful to the heart and blood vessels.

The study, published in AHA’s journal Circulation, suggests that cannabis should be removed from the federal Drug Enforcement Agency’s Schedule 1 controlled substances list so that it can be studied more closely.

While still illegal to grow, sell, or use at the federal level, cannabis is legal for some form of use in 47 states and the District of Columbia.

“We urgently need carefully designed, prospective short- and long-term studies regarding cannabis use and cardiovascular safety as it becomes increasingly available and more widely used,” Robert L. Page II, chair of the writing group for the statement, said in a news release. “The public needs fact-based, valid scientific information about cannabis’s effect on the heart and blood vessels. Research funding at federal and state levels must be increased to match the expansion of cannabis use – to clarify the potential therapeutic properties and to help us better understand the cardiovascular and public health implications of frequent cannabis use.”

According to the AHA, observational studies have linked the chemicals in marijuana to an increased risk of heart attacks, heart failure, and a heart rhythm disorder called atrial fibrillation, the report said. One study cited in the report suggests that 6 percent of heart attack patients under age 50 use cannabis. And other research cited in the report indicated that cannabis users between the ages of 18 and 44 had a significantly higher risk of having a stroke compared to non-users.

“Unfortunately, most of the available data are short-term, observational and retrospective studies, which identify trends but do not prove cause and effect,” said Page, who is also a professor in the department of clinical pharmacy and the department of physical medicine/rehabilitation at the University of Colorado in Aurora. “Health care professionals need a greater understanding of the health implications of cannabis, which has the potential to interfere with prescribed medications and/or trigger cardiovascular conditions or events, such as heart attacks and strokes,” he said.