Thursday, November 7, 2013 by:Jake Ellison

Researchers and advocates of public health can often come across as “The People Who Say, Don’t!” Then, knowing human nature, they’ll add with a headshake: “But if you have to, then for goodness sake protect yourself.”

And you can’t blame them.

When you look at big numbers, broad statistics, the individual gets lost in what can be dire, expensive and preventable public health disasters: overeating, STDs, problems related to alcohol consumption … and one of the worst habits causing the most headshaking: Smoking.

Consequently, when it comes to smoking marijuana, health experts wish people would not add one more thing into their lives that could cause trouble for themselves and society. That said, there are reason humans have sex, drink, smoke and take drugs. And, some of those reasons are very good ones, such as taking a drug to relieve pain or treat a disease.

Enter Paul Armentano, the Deputy Director of NORML — the National Organization for the reform of Marijuana Laws. He is the co-author of the book, Marijuana Is Safer: So Why Are We Driving People to Drink? (Chelsea Green, 2013)

Armentano contacted us after he read a sponsored blog post on our Big Blog: “Sponsored Post: Marijuana Smoking and the Risk of Lung Cancer: Time for Pause.” The post was written by Dr. Eric Vallieres, surgical director of the Lung Cancer Program at the Swedish Cancer Institute. (Sponsored blog posts are paid advertisements.)

Armentano wanted to clarify what research says about the dangers to your lungs from smoking weed, and this is the right forum for that.

So, here’s what he wrote us:

No one argues that the ingestion of combustive smoke, whether it is tobacco smoke or cannabis smoke, is healthy. However, it is inaccurate to allege that the risks to the consumer posed by these two substances are equal.

Writing in the prestigious Journal of the American Medical Association (JAMA) in 2012, researchers from the University of California, San Francisco reported that occasional to moderate cannabis consumption was not associated with the adversely pulmonary risks associated with tobacco smoking.

Investigators “confirmed the expected reductions in FEV1 (forced expiratory volume in the first second of expiration) and FVC (forced vital capacity)” in tobacco smokers.

By contrast, “Marijuana use was associated with higher FEV1 and FVC at the low levels of exposure typical for most marijuana users. With up to 7 joint-years of lifetime exposure (e.g., 1 joint/d for 7 years or 1 joint/wk for 49 years), we found no evidence that increasing exposure to marijuana adversely affects pulmonary function.” The full study may be read online.

The findings in JAMA were hardly a surprise. Previously, the largest case-controlled study ever to investigate the respiratory effects of marijuana smoking reported that cannabis use was not associated with lung-related cancers, even among subjects who reported smoking more than 22,000 joints over their lifetime.

Summarizing the study’s findings in The Washington Post, lead investigator and pulmonologist Dr. Donald Tashkin of UCLA concluded, “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.” The full study is available online.

More recently, this past May presenters at the annual meeting of the American Academy for Cancer Research reported that subjects who regularly inhale cannabis smoke possess no greater risk of lung cancer than do those who consume it occasionally or not at all — according to an analysis of six case-control studies, conducted between 1999 and 2012, involving over 5,000 subjects (2,159 cases and 2,985 controls) from around the world.

They concluded, “Our pooled results showed no significant association between the intensity, duration, or cumulative consumption of cannabis smoke and the risk of lung cancer overall or in never smokers.”

Most recently, an editorial in July published in the journal Annals of the American Thoracic Society concluded: “Cannabis smoking is not equivalent to tobacco smoking in terms of respiratory risk. … [C]annabis smoking does not seem to increase risk of chronic obstructive pulmonary disease (COPD) or airway cancers. In fact, there is even a suggestion that at low doses cannabis may be protective for both conditions. … This conclusion will affect the way health professionals interact with patients, parents with teenagers, and policy makers with their constituents. … Efforts to develop cleaner cannabinoid delivery systems can and should continue, but at least for now, [those] who smoke small amounts of cannabis for medical or recreational purposes can breathe a little bit easier.”

It is true that some studies of cannabis smoke and pulmonary function indicate that chronic exposure may be associated with an increased risk of certain respiratory complications, including cough, bronchitis, phlegm.

That said, the ingestion of cannabis via alternative methods such as edibles, liquid tinctures, or via vaporization – a process whereby the plant’s cannabinoids are heated to the point of vaporization but below the point of combustion – virtually eliminates consumers’ exposure to such unwanted risk factors and has been determined to be a “safe and effective” method of ingestion in clinical trial settings.

Cannabis smoking is certainly not without potential risks. But these risks should not be overstated, nor should they be asserted as a justification for a public policy that continues to criminalize and stigmatize responsible, adult cannabis consumers.

Jake Ellison can be reached at 206-448-8334 or Follow Jake on Twitter at Also, swing by and *LIKE* his page on Facebook.