Passive smoking of cannabis more harmful than tobacco

A Californian study claims that passive smoking of weed is more dangerous than smoking tobacco.

Published in the Journal of the American Heart Association, the study suggests more harmful effects on the arteries. For the moment, all studies comparing the two smokes inhaled directly (and not as secondary inhalation), put cannabis smoke at a healthier level than tobacco smoke.

Researchers from the Department of Cardiology at the University of San Francisco are behind this study. Basing their tests on rats, they studied blood vessel activity after one minute of passive smoking. They found that blood vessel activity was altered for almost an hour and a half by cannabis. That's three times longer than in rats exposed to cigarette smoke.

Mathew Spinger, who led this study, comments on the facts: «Although the effect is only temporary for both smokes, over the long term it can affect elasticity and clog arteries. The THC, like nicotine, is not the cause of the problem. The paper used for rolling is also cleared. It's the smoke itself that's dangerous. The idea that cannabis smoke is benign has to go. We just didn't have the proof.»

However, the research was not carried out on humans for cannabis smoke. The scientists based their findings on the fact that, since rats react to tobacco smoke in the same way as humans, they deduced that the same was true of cannabis. What's more, the scientists didn't determine why cannabis altered a rat's blood circulation for 1.5 hours, whereas cigarettes did for 30 minutes.

In 2014, a study showed that the risk of heart problems increased fivefold immediately after smoking cannabis. This study was also based on the short term. Visit long-term cannabis studies is rare at the moment, we don't know exactly what the dangers of cannabis are. Cannabis users will have to wait for a relaxation of cannabis laws, and therefore for more studies on the subject, to be sure of the long-term effects on the body.