Marijuana Could Increase Adverse Cardiovascular Conditions

Medical marijuana has been touted as a treatment for numerous conditions, ranging from multiple sclerosis to cancer, despite limited scientific evidence.

A new study published by the European Journal of Preventive Cardiology suggests that marijuana use is linked to a 3-fold increase in hypertension-related mortality.

"Steps are being taken towards legalisation [sic] and decriminalisation [sic] of marijuana in the United States, and rates of recreational marijuana use may increase substantially as a result," said lead author Barbara A. Yankey, a PhD student at Georgia State University. "However, there is little research on the impact of marijuana use on cardiovascular and cerebrovascular mortality."

Due to a lack of longitudinal data on marijuana use, the authors created a retrospective follow-up to the National Health and Nutrition Examination Survey, which included participants age 20 and older. In the original study, patients were asked if they had ever used marijuana.

The authors characterized participants who used the drug as marijuana users. The authors also calculated the duration of marijuana use.

This information was integrated with 2011 mortality data from the National Centre for Health Statistics. The authors projected the associations of marijuana use and duration of use, with mortality related to hypertension, heart disease, and cerebrovascular disease, according to the study. Factors such as cigarette use and demographic variables were controlled for.

Overall, data for 1213 patients were included in the current study.

The authors discovered that marijuana users had a heightened risk of hypertension-related mortality. Compared with non-users, this population was 3.42 times more likely to die from hypertension, with the risk increasing 1.04 times each year of use, according to the study.

"We found that marijuana users had a greater than 3-fold risk of death from hypertension and the risk increased with each additional year of use,” Yankey said.

The authors did not observe an association between marijuana and heart disease-related or cerebrovascular disease-related death.

However, the authors advise that there were limitations to the study, including that they were unable to determine if participants continuously used marijuana once they first tried it.

"Our results suggest a possible risk of hypertension mortality from marijuana use. This is not surprising since marijuana is known to have a number of effects on the cardiovascular system,” Yankey said. “Marijuana stimulates the sympathetic nervous system, leading to increases in heart rate, blood pressure and oxygen demand. Emergency rooms have reported cases of angina and heart attacks after marijuana use."

The investigators report that cardiovascular risks for marijuana may be higher than the risks associated with cigarettes, according to the study.

"We found higher estimated cardiovascular risks associated with marijuana use than cigarette smoking," Yankey said. "This indicates that marijuana use may carry even heavier consequences on the cardiovascular system than that already established for cigarette smoking. However, the number of smokers in our study was small and this needs to be examined in a larger study. Needless to say, the detrimental effects of marijuana on brain function far exceed that of cigarette smoking.”

The authors concluded that it is crucial to understand the health effects of marijuana to better inform policy decisions, according to the study.

"Support for liberal marijuana use is partly due to claims that it is beneficial and possibly not harmful to health. With the impending increase in recreational marijuana use it is important to establish whether any health benefits outweigh the potential health, social and economic risks,” Yankey said. “If marijuana use is implicated in cardiovascular diseases and deaths, then it rests on the health community and policy makers to protect the public."