Study Finds Emphysema Risk Could Be Higher In Marijuana Smokers Than Cigarette Smokers


Marijuana growers and users have been clamoring for the legalization of the drug for decades, but now that it’s finally legal in 21 states, many people and health experts are wondering about its possible adverse health effects, especially its impact on the lungs.

A new study, which was published in the journal of the Radiological Society of North America, Radiology, suggest that marijuana smoking could actually be more dangerous than cigarette smoking. What it discovered is that emphysema, which happens to be a lung condition that causes shortness of breath, as well as airway inflammation, has become more common in marijuana users than those that smoke cigarettes.Moreover, this study also backs previous evidence seen in animals and humans that prove the link between marijuana use and an increased possibility of developing emphysema. However, it also contradicts other research that shows how marijuana is actually less harmful to the lungs as compared to tobacco.

Professor of psychiatry and behavioral sciences at Stanford University, Keith Humphreys, PhD, whose research also looks into tobacco and marijuana addiction shares, “The results are unexpected and a replication study seems warranted — tobacco smokers consume many more cigarettes a day than cannabis smokers, so we would expect higher rates of irritation in the respiratory system as a result.”

Dr. Humphreys, who wasn’t part of the study, adds, “But at the same time, we still don’t understand all the components of the cannabis plant and it may have some unique ability to do damage to the airways that has not been studied.”

This study, which was led by researchers from the University of Ottawa in Canada, shares that the study looked at chest computerized tomography (CT) scans from 56 marijuana smokers and compared them with the scans of 57 nonsmoking controls, as well as 33 tobacco-only smokers.

What they saw in the X-ray images was that ‘three-quarters of the marijuana smokers had emphysema compared with 67 percent of the tobacco-only smokers. Nonsmokers fared much better, with just 5 percent of them showing signs of emphysema.’

Moreover, the scientists also noted that Paraseptal emphysema, which is a type of emphysema that damages that tiny ducts which connect the air sacs in the lungs, was the most predominant subtype of emphysema in marijuana smokers as compared to the tobacco-only smoking participants.

Their CT scans also revealed that airway inflammation was more frequent in the marijuana smokers as compared to the non-smokers and tobacco-only smokers. Furthermore, there was an increase in the amount of breast gland tissues in the boys or men – known as gynecomastia – which, explained by May Clinic, is often caused by the imbalance of estrogen and testosterone hormones by 38 percent in the marijuana users as compared to just 11 percent of the tobacco-only smokers and just 16 percent in the controls.

As for cardiothoracic radiologist, assistant professor at the University of Ottawa, and lead study author, Giselle Revah, MD, she describes the study results as “surprising,” since the participants that were part of the tobacco-only group had a considerable smoking history.

She explains in a statement, “The fact that our marijuana smokers — some of whom also smoked tobacco — had additional findings of airway inflammation/chronic bronchitis suggests that marijuana has additional synergistic effects on the lungs above tobacco.” This means that the results show a combined effect on the lungs that could be worse than how either drug affects the lungs alone.

Moreover, Dr. Revah and her colleagues also share that regardless of the participants’ ages, their risks for emphysema and airway inflammation were almost the same.

Although the study wasn’t able to determine the actual reasons of the different results for the marijuana and cigarette smokers, they did come up with some possibilities. Since marijuana is usually smoked unfiltered while tobacco is more often smoked with a filter, it’s possible that there are more particulates that enter the lungs of the marijuana smokers. Plus, marijuana is usually inhaled with the breath held longer, as well as a higher volume of smoke as compared to cigarettes.

Revah also said in a press release, “It has been suggested that smoking a marijuana joint deposits four times more particulates in the lung than an average tobacco cigarette. These particulates are likely airway irritants.”

In the end, the research group also shares that more research and studies are required involving bigger groups of people, as well as collecting more data on how much and how often people smoke to get more information. They also share that by observing the different inhalation techniques, whether they smoke joints or use pipes or bongs, could provide more pertinent data.

Humphreys shares, “Marijuana has been marketed as harmless, indeed even as a cure for many diseases. But the truth is that the drug itself, as well as the act of smoking anything, can damage your body.”