Posted June 4, 2013 by evergreen-culture in Marijuana Myths

Myth: Marijuana Smoking Causes Lung Cancer


e at Evergreen Culture do not believe that all the information that has been put out concerning cannabis is necessarily fueled by a desire to deliberately mislead. We also don’t believe that everything said is crazy or sounds out of the realm of possibility. Decades ago it was surmised that if smoking cigarettes caused cancer, and if many of the same carcinogens were present in marijuana smoke, it would make sense that the risk of lung cancer was there. This hypothesis, quoted extensively by anti-cannabis groups and governmental drug-enforcement agencies over the last 30 years, was first put forth by Donald Tashkin, a UCLA Pulmonologist. He surmised – logically so to a large extent – that because most marijuana smokers inhale deeply and hold the smoke in (by the way, this does nothing for the quality or strength of effects as the cannabinoids are taken up almost immediately and don’t require holding the smoke in) the risk of lung cancer was there, and possibly even greater than with cigarette smoking.

Donald Tashkin, a pulmonologist at UCLA, has studied marijuana for 30 years. Furthermore, Tashkin’s work has previously established a tenuous link between marijuana smoking and negative health effects. For example, he found that marijuana tar contained higher concentrations of cancer-causing substances, and because of that and the fact that marijuana smokers hold smoke deep in their lungs for an extended period of time, it previously seemed likely that the health effects of prolonged exposure would become increasingly damaging.

Read more: http://www.addictinginfo.org/2013/05/15/study-smoking-pot-cause-lung-cancer/#ixzz2VGmDl4PH

But here is the rub, those statements were not based on evidence. There had been years of study and evidence around tobacco smoking and its clear link to lung cancer. However, these hypotheses around marijuana smoking and lung cancer were based not on any study data (as none was available) but on leaps of logic that certainly weren’t illogical, ill-intended or meant to do anything but inform and protect to the best of the medical establishment’s ability at the time.

What a difference 30 years makes.

Three decades later finds us with a mountain of evidence and, more importantly, a significant study by the very man who made the original statements concerning the danger of lung cancer due to smoking cannabis.

Earlier work established that marijuana does contain cancer-causing chemicals as potentially harmful as those in tobacco, he said. However, marijuana also contains the chemical THC, which he said may kill aging cells and keep them from becoming cancerous.

They were all asked about their lifetime use of marijuana, tobacco and alcohol. The heaviest marijuana smokers had lighted up more than 22,000 times, while moderately heavy usage was defined as smoking 11,000 to 22,000 marijuana cigarettes. Tashkin found that even the very heavy marijuana smokers showed no increased incidence of the three cancers studied.

“This is the largest case-control study ever done, and everyone had to fill out a very extensive questionnaire about marijuana use,” he said. “Bias can creep into any research, but we controlled for as many confounding factors as we could, and so I believe these results have real meaning.” (The Washington Post)

Read more: http://www.addictinginfo.org/2013/05/15/study-smoking-pot-cause-lung-cancer/#ixzz2VGnUNfp9

So the actual conclusions based on scientific study shows that even heavy marijuana smokers have no increased risk of lung cancer over a controlled group of non-smokers. The complete opposite of the hypothesis set forth prior to the study. But this is what the scientific method is for – testing hypothesis to determine if it is true or if it needs to change. In the case of this idea, the science turns it on its head entirely.

Here is a clear sign that you can likely trust information being presented to you: if the very person who put forth the original statement overturns their own professionally-offered conclusions based on scientific study and careful consideration of the evidence and the facts that can be derived from it. When someone says, “I was completely wrong and here is why I know that” there is a very good chance you can consider what they are saying as trustworthy.

Here is a case of a myth put forth 30 years ago, a myth that has been perpetuated and used as fuel in the marijuana debate as a clear reason for keeping this “dangerous drug” away from the unsuspecting public. But along comes scientific facts, vast study evidence, and luckily a medical professional who is willing to confront ideas no longer able to held in fact, even when the ideas were their very own, essentially disproving their earlier work in the eyes of their medical peers and the public.

From now on, if you hear the idea that marijuana smoking is a ticket to lung cancer and thus shouldn’t be legalized, you can call bullshit based on science. And the very fact that something that seems like it should be true actually isn’t due to the interworking between the cannabinoids in marijuana and cannabinoid receptors in the human body should create pause when considering other statements about marijuana being dangerous, addictive, making you stupid, causing schizophrenia and the like. Out of all of the supposed dangers, the lung cancer thing seems the most likely, and yet pure scientific fact has shattered that myth.

It is clear that marijuana needs to be looked at with a fresh perspective – as was done in Dr. Tashkins’ study – so that we can reframe it in facts rather than fictions, propaganda, and misinformation being parroted by the unqualified and ignorant. Anyone quoting Dr. Tashkin’s previous statements around the risk of lung cancer through marijuana smoking is deliberately choosing to perpetuate misinformation directly contradicted by scientific fact.

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