Donald Tashkin, MD: Advancing Marijuana Lung Health Trials

In the past 2 decades, Donald Tashkin, MD, has been a leading voice in the clinical assessment of marijuana’s effect on users’ lung health. In 2006, he presented findings at the American Thoracic Society (ATS) International Meeting showing that—after controlling for various substance use and patient characteristic factors—that marijuana smoke is not associated with an increased risk for lung cancer.

Since then, the emeritus Professor of Medicine at UCLA has led efforts into understanding marijuana’s effects and associations with other pulmonary conditions including chronic obstructive pulmonary disease (COPD). At ATS 2019—the 13^th anniversary of his team’s presentation of pivotal findings—Tashkin talked with MD Magazine® about what it’ll take to more wholly, comprehensively understand the lung health of marijuana smokers.

Namely, it’ll take a lot of time, a lot of real-world data, and the acceptance that most of that data is coming from recreational users.

MD Mag: Are federal and state regulations regarding marijuana legalization critical in advancing studies addressing their effect on lung health?

Tashkin: I think that most of the use is going to be recreational, rather. There's a fair amount of medicinal use, but it's probably mostly recreational—even among those who claim that they're taking it for medicinal properties. And all these studies essentially have to be real-world studies. You can't do a randomized controlled trial, in which case it will be important to not standardize the dose, etc. It's never going to happen.

So you have to rely upon the general population of people who smoke as much as they want, and as long as they want, etc. So, I don't think that federal regulations regarding dose and purity, and so forth will affect that.

It doesn't mean it's going to be easy to do. I think, as the traveling to marijuana use increases, you're going to find there'll be more opportunity to do this kind of study. But you'll have to wait for a while, because it takes a long time for cancer to develop—even a long time for COPD to develop, a long, latent period. We need long-term studies, particularly among heavier smokers, but if there's a link of association, it would be in the heaviest users.