A new study finds young and middle-aged adults who use marijuana may have an increased risk for heart-related complications.

The paper, published in the Journal of the American Heart Association, found nearly 2 percent of health complications from marijuana use were linked to cardiovascular health, and a quarter of these complications resulted in death.

"This result is consistent with previous findings and strengthens the idea that cannabis may be responsible for serious complications, in particular on the cardiovascular system," write the authors in their study. "Cannabis may trigger cardiovascular complications and therefore should be regarded as so by health practitioners and by users, who often admit the dangers of drugs like cocaine and amphetamines but minimize that of cannabis."

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For the study, researchers in France looked at data from the French Addictovigilance Network between 2006 and 2010. They identified 35 out of nearly 2,000 marijuana-users with known medical conditions linked to the heart and arteries in the brain or limbs. The majority of the patients were male with an average age of 34.

In their analysis, the researchers found 22 out of 35 had heart problems, and 20 suffered a heart attack. Ten of the 35 cases were linked to diseases in the arteries of their limbs, while three were associated with arteries in the brain. Nine out of the 35 patients died from cardiovascular complications.



The authors say they suspect the number of cardiovascular-related health complications and deaths among marijuana users is actually much higher than the data suggests, since many incidences go unreported and it's often difficult to detect which substance is linked to health problems. Studies have found people who use marijuana are also more likely to develop dependence on other drugs and alcohol.

Dr. Robert Kloner, director of research at the Heart Institute of Good Samaritan hospital in Los Angeles, agrees with the study authors. "We used to think marijuana was a very safe drug. But as more and more marijuana is being used there have been more identifiable cases of cardiovascular complications," he told CBS News. "It can increase heart rate and this can increase the demand for oxygen by the heart."

As more states in the U.S. legalize marijuana for recreation and medical use, some experts are calling for a national system to track health complications related to use of the drug.

Dr. Sripal Bangalore, an associate professor of medicine in the Division of Cardiology at NYU Langone Medical Center, says this study adds to a sizable body of research on the health impact of recreational marijuana use. "One is left to wonder whether we need to consider 'pot heart' in addition to 'pot head,'" he told CBS News in an email. He notes that it is difficult to separate out the effects of marijuana in people who may also smoke tobacco, drink alcohol or use illicit drugs. "Nevertheless," he says, "the growing body of evidence suggests that similar to statutory warning on smoking, similar warning should perhaps be considered for recreational marijuana use."