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Does Marijuana Cause Lung Damage?

By on January 27, 2013

Summary (click to view)

• Marijuana and tobacco smoke contain similar cancer-causing compounds
• Marijuana smoke also contains anti-cancer and anti-tumor compounds known as cannabinoids (eg. THC and CBD)
• Studies show that regular marijuana use does not harm lung function or lead to lung cancer
• Experts believe THC may have a protective effect on the lungs
• Marijuana smokers are still at risk of mild conditions like chronic bronchitis – Most people are aware that tobacco use can lead to numerous lung problems, including impaired breathing and, in some cases, cancer.

While usually seen as less harmful, smoking marijuana is also thought to be bad for your lungs. But is this a myth or reality?

Marijuana Vs. Tobacco

The smoke from burning marijuana flowers contains several cancer-causing compounds, similar to those found in tobacco smoke.

Worse, cannabis smoke deposits a hefty amount of carcinogen-containing tar into the lungs – up to 4 times as much as cigarettes do, according to some studies. This is due to the way marijuana joints are usually rolled (loosely packed and unfiltered).

On the other hand, the smoke from marijuana contains a set of unique chemicals known as cannabinoids (eg. THC and CBD), which are not found in cigarette smoke. Numerous studies have found cannabinoids to have significant anti-cancer and anti-tumor effects.

This key difference is believed to play a role in the different outcomes that marijuana and tobacco have on the lungs.

What The Studies Show

Over the past decade, two large-scale studies have set out to determine the impact of heavy, sustained marijuana use on the lungs.

The first of these studies was led by Dr. Donald Tashkin – a federal researcher and lung specialist who has conducted over 20 years of research on marijuana and the lungs through generous grants from the National Institute on Drug Abuse (NIDA).

In 2006, Dr. Tashkin co-authored a study involving over 2,000 people, which found that, unlike tobacco, marijuana use did not increase the risk of lung cancer, even in individuals who reported smoking over 20,000 marijuana joints in their lifetime. On the contrary, the results seemed to show a reduction in cancer risk.

“We hypothesized that there would be a positive association between marijuana use and lung cancer, and that the association would be more positive with heavier use… What we found instead was no association at all, and even a suggestion of some protective effect.” – Dr. Tashkin

The second study was published in 2012 by a separate team of researchers from the University of California. It was the largest study ever to be conducted on marijuana smokers and involved a sample of over 5,000 adults. The researchers followed their subjects over a 20-year period and found that regular marijuana use – defined as a joint a day for 7 years or a joint a week for 20 years – had no impact on lung function.

Both studies included a sample of tobacco smokers for comparison, and both were able to confirm what we already know – cigarette smoking is directly correlated with lung cancer and impaired lung function. On the other hand, marijuana doesn’t seem to pose the same risks.

The Explanation

Although some experts have been baffled by the results of the two studies mentioned above, Dr. Tashkin points to an obvious explanation. He notes that the THC compound in marijuana may protect users against lung cancer by counteracting the effects of other cancer-causing compounds.

This theory is supported by an abundance of evidence that demonstrates the anti-tumoral and anti-cancer effects of various cannabinoids, including THC. In fact, studies involving rats have found THC to help fight tumor growth specifically in cases of lung cancer.

“The THC in marijuana has well-defined anti-tumoral effects that have been shown to inhibit the growth of a variety of cancers in animal models and tissue culture systems, thus counteracting the potentially tumorigenic effects of the procarcinogens in marijuana smoke.” – Dr. Tashkin

Other properties of THC may explain why marijuana users are not at risk of chronic obstructive pulmonary disease (COPD). COPD is a long-term lung disease that commonly affects tobacco smokers, but does not appear to occur in marijuana users.

“We don’t know for sure… but a very reasonable possibility is that THC may actually interfere with the development of chronic obstructive pulmonary disease.” – Dr. Tashkin

Risks of Marijuana Smoke

Although marijuana smokers may have little to worry about when it comes to cancer and impaired lung function, studies show that marijuana use can still lead to mild lung problems like chronic bronchitis.

Chronic bronchitis is caused by inflammation of the airway. The condition is characterized by the following symptoms:

Persistent cough
Extra mucus/phlegm production

Studies show that patients without noticeable impairment of lung function can still be suffering from chronic bronchitis. Unfortunately, there is no medication that can be prescribed for symptoms of chronic bronchitis caused by smoking. The best method of prevention and treatment is to simply stop smoking – even just for a temporary period of time.

Vaporizing — Is it Safer?

If you suspect you may be suffering from chronic bronchitis and stopping marijuana use is not an option, investing in a vaporizer may be your best bet. A study published in 2010 showed that marijuana smokers who switched to vaporizing experienced significant reductions in symptoms following one month of use.

Health professionals recommend vaporizers for most patients who use medical marijuana. Vaporizers allow the plant matter to be heated enough for cannabinoids to be released, but not enough to cause combustion, thereby eliminating the harmful by-products normally found in smoke.

By using a vaporizer, the risks of airway inflammation associated with marijuana smoke may be avoided.

  • BillyBoy80


  • xlxTrinityxlx

    Thank God for this article. I just used all of this info to shit on my parents in the argument that marijuana was unhealthy for me and my asthma. They now respect me more after realizing I’m not throwing my life down the drain.

    • dbspambox

      As a regular user myself, I think you need to be aware that it has a detrimental effect on short term memory, and I personally would never recommend regular use for anyone under the age of 18 (or maybe even 21). Brains never stop developing, but adolescence is especially important. I wasn’t using daily until I was well into my 20s. It’s been over 10 years now and I’m still very smart and excel at my high functioning job (in IT). My memory has always been bad, but weed has made it a little worse. I’ve also recently switched to vaporising and my lungs feel better than ever. And I’m also a mild asthmatic.
      The other thing is that smoking anything still puts tar and carbon monoxide into your blood, so if recovering from surgery, or have cuts and stuff, your risk of infection is increased, and you won’t heal as fast. There are some very good and fun and portable vaporisers out there. They do take some practice to use though.

    • none

      We were just trying to help you honey. we love you

  • Afshin Nejat

    Ah, a negative correlation… either the anti-carcinogenic effects of Cannabis are causally related to this, or else we must assume the average “pot head” simply lives a healthier lifestyle in general, so much so that they are generally less likely to get cancer than the average person who smokes nothing at all. So… when was the last time you saw Joe Joint Puffer living a “healthy lifestyle” per se? The odds are, Cannabis is so anti-carcinogenic that it is not only useful to combat existing cancers in a patient when used in concentrated and frequent dosing regimens, but in fact just regular smokers generally benefit from it!

    Can your cigarette industry lobby make a similar argument for their product? No, but look how legal THAT is. Look at all the DEATH cigarettes and alcohol are directly and indirectly implicated in causing! Yet what do they demonize for decades and decades, even after studies prove that all their lies and rhetoric are just that? They demonize something that people enjoy and which doesn’t make them any money, and in fact cuts INTO their profits with regard to the pseudo-medical farce over which the demonic AMA acts as the ringleader and cheerleader, the liaison between death, dehumanization, illness, and control of people through governmental corruption which answers to oligarchic influence. Cannabis simply cramps their style on all fronts! Especially in that it is beneficial for many, grown out of the ground, and useful for so many things you could BASE AN ECONOMY UPON IT.

    Well, I’d rather admit facts and face reality than be one of the many morons who just need a pat on the back from the Mayor of Pleasantville to feel good about shooting themselves in their heads. They may claim that knowing the truth of matters is silly, crazy, loony, etc, but let’s just remember the kettle and pot, don our imaginary tinfoil hats, and send out a general “FU” to the lemmings who have no respect for reality, but speak of the question of others’ sanity.