A pulmonologist, advise all patients not to smoke anything

According to researchers, the smoke of cannabis and tobacco say they may be similar in how they damage
the lungs.

For instance, pulmonologist Dr. Donald Tashkin, emeritus professor of medicine at the David Geffen School of Medicine, UCLA, told NBC News:

“The smoke of marijuana contains many of the same volatile chemicals found in tobacco smoke that are injurious to lung tissue.” 

“As a pulmonologist, I advise all my patients not to smoke anything,” Tashkin said.

On the surface, pot smokers would seem to be at a lower risk than cigarette smokers because they light up fewer times a day. But researchers have found that far more carcinogens, like tar, end up in the lungs when a joint is smoked than a cigarette.

This is as a result of the fact that the way marijuana is smoked is different  to a normal cigarette. Traditional vaping or joint smoking usually involves inhaling the marijuana smoke deeply into the lungs and holding it in, which gives the toxins more contact with the lungs. Also, many marijuana users smoke a joint all the way to the end.

Tar, the sticky stuff left after burning, is concentrated at the end of a joint and contains high levels of harmful substances that can injure lung cells.

Some research has shown that smoking one joint is comparable to smoking anywhere from four to 20 cigarettes. These findings are one reason why Tashkin expected to find a link between smoking pot and developing lung cancer.

“Regular smoking of marijuana by itself causes visible and microscopic injury to the large airways that is consistently associated with an increased likelihood of symptoms of chronic bronchitis that subside after cessation of use,” Tashkin wrote in a 2013 study on the effects of habitual marijuana use on the lungs.

Though, he also found that pre-cancerous alterations developed in the lungs, but it often did not lead to cancer.

“In human studies of long-term marijuana users, we found widespread pre-cancerous changes on the lungs,” Tashkin said. “That doesn’t mean that if you have these changes you will develop lung cancer. But if it’s there you are at an increased risk of doing so.”

According to Tashkin, who has co-authored numerous studies on the impact of marijuana on the lungs over the past 30 years, has even re-analyzed his own data, he only found an increased risk of lung cancer in heavy smokers in a small number of patients. The number was so small that Tashkin didn’t believe it could be used as firm evidence to support the conclusion that pot could cause cancer.