Marijuana use increases the risk of stroke by 26 percent and heart failure by 10 percent, a new study has found.

Cardiologist Aditi Kalla and her team at the Einstein Medical Center in Philadelphia will present their findings on Saturday at a meeting of the American College of Cardiology in Washington, D.C.

It’s stone cold news for California — a state that legalized recreational pot use four short months ago. But “the side effects shouldn’t preclude it from being legalized or prescribed,” Kalla said in an interview Wednesday.

“Cannabis is an independent risk factor for heart failure and stroke,” she said. “It needs to be considered a risk factor, but it shouldn’t affect the prescription of it.”

Examining medical records from a publicly available database, called the Nationwide Inpatient Sample, Kalla’s team looked at more than 20 million records of patients aged 18 to 55 who were discharged in 2009 and 2010, finding that 316,000 of them had used marijuana. Those individuals had a significant increase of stroke, heart failure, coronary artery disease and sudden cardiac death, the researchers reported.

Heart problems could easily be attributed to other health conditions or risk factors such as high blood pressure, obesity, alcohol use, diabetes and smoking. But the study was adjusted to rule out these factors, according to the American College of Cardiology.

“What does that mean? If you’re a marijuana user and you have chest pain, it might be a heart attack. If you have neurological changes, like motor function loss or sensation loss, it might be a stroke,” said Dr. William Abraham, director of cardiovascular medicine at the Ohio State University.

If you experience any of those symptoms, “it might be wise to seek medical attention sooner,” he added.

Scientists — and many members of the general public — already know that marijuana use affects the heart and circulation. We know it’s affiliated with irregular heartbeats, weakened heart muscles and chest pain, Abraham said, and its use can raise heart rates by as much as 100 percent. The new study contributes to this growing body of information, he added.

But overall, heart attack or failure is relatively rare in pot users.

“Marijuana users need to know there’s a risk here, although quantitatively the risk is quite small,” Abraham said.

Matt Springer, a professor of medicine in UC San Francisco’s cardiology division, whose research group examined the harmful effects on blood vessels from secondhand marijuana smoke in rats, believes whether the drug leads to heart problems is still an unknown.

“We’re talking blind about this stuff,” he said.

Several large-scale studies have searched for ties between marijuana use and cardiovascular effects, he said. Some found links and some didn’t, which he said means further study is warranted.

“We’re all seeing different pieces of this,” Springer said. “Animal studies like mine have limitations; human association studies like this one have limitations. And somewhere in the middle of all of them is the truth.”

Another concern: Studies about marijuana use rarely distinguish between smoking, vaping and edibles. When the ingestion strategy is neglected, scientists have no way of knowing if negative effects stem from the chemical gateway to euphoria — THC — or from inhaling smoke, Springer explained.

But he realizes the study provides enough reason to believe the drug isn’t magic. Various aspects of it can be harmful.

“When people use marijuana they should do it with their eyes open,” he said. “That being said, it appears it does have some beneficial effects,” such as treating epilespy and reducing nausea in cancer patients being treated with chemotherapy.

It was an opinion shared by the dozens of patients gathered Wednesday at MMJ Doctor in downtown San Jose.

On the surface, the medical marijuana dispensary’s reception room looks like any other doctor’s office: A small television shows the movie “E.T.” and jittery patients scribbling out forms on clipboards. But there’s a ATM in the corner, and the magazines on the table aren’t the typical “People” and “Women’s Health”– they’re the March issue of “Dope.”

Joe Lagattuta, 52, on Wednesday was a first-time patient at the downtown clinic. But he’s been smoking marijuana recreationally for about 35 years, except for when he worked briefly as a truck driver. His new job as a meat-cutter at Whole Foods allows him to smoke after work and on weekends.

Lagattuta said isn’t worried about the potential link between marijuana and heart health.

“As far as marijuana goes,” he said. “If it lowers blood pressure and stress, it has to be positive — because I know that stress kills, too.”

Kalla emphasizes that she and her team of cardiology researchers aren’t anti-cannabis. Rather, they hope that doctors can keep patients like Lagattuta well-informed in the future.

“Our purpose isn’t to criminalize it. We just want to make sure if a patient asks about it we can give them as much information as possible,” she said. “You know how someone who’s drank a lot the night before says ‘My liver hates me right now?’ If someone smokes a lot, I want them to say ‘Oh God, I got to get my heart checked out tomorrow.’”