A new study from the University of Otago has uncovered important differences in how cannabis and tobacco affect lung health. This research comes at a time when cannabis use is becoming more widespread across the world, making its findings especially relevant.
Led by Professor Bob Hancox, the study reveals that long-term cannabis use significantly changes lung function, in ways that are quite different from tobacco smoking.
One of the key discoveries of the study is that cannabis tends to over-inflate the lungs and creates more resistance to airflow than tobacco. This means that cannabis smokers often struggle to breathe out properly, as their lungs hold onto more air than they should.
Even more surprising is that cannabis smoking seems to reduce the lungs’ ability to extract oxygen from the air—a problem that has typically been associated only with tobacco smoking. This finding challenges the common belief that only tobacco severely harms lung function in this way.
The research draws its data from the Dunedin Multidisciplinary Health and Development Study, which has followed over 1,000 people born in Dunedin, New Zealand, in 1972 and 1973.
These participants have been monitored for more than four decades, providing a rare, long-term look at the effects of smoking cannabis. Because the study spans such a long time, it offers solid evidence about the impact of lifelong cannabis use on the lungs.
One of the most striking findings is the presence of a condition nicknamed “bong lung” among heavy cannabis users. This condition is a form of emphysema, which is characterized by damage to the tiny air sacs in the lungs that are responsible for oxygen exchange.
Until now, emphysema has been mostly linked to long-term tobacco use, but the study shows that regular cannabis smoking can cause similar damage. According to the researchers, the appearance of “bong lung” in heavy cannabis users is a clear sign of how marijuana can harm lung tissue over time.
The study also confirms that the effects of cannabis and tobacco are not the same. While both substances damage the lungs, they do so in different ways. Tobacco tends to cause more narrowing of the airways, leading to conditions like chronic obstructive pulmonary disease (COPD), while cannabis appears to affect lung inflation and oxygen exchangemore dramatically.
Professor Hancox explained that smoking both substances together can make the damage even worse, leading to compounded health problems.
These findings are especially important as more countries are moving towards decriminalizing or legalizing cannabis. Understanding how cannabis affects the lungs differently from tobacco is crucial for health policies and medical guidelines. As cannabis becomes more accessible, both doctors and lawmakers will need to consider the risks of long-term lung damage.
Professor Hancox stressed the need for further research to understand exactly why cannabis has these unique effects on the lungs. He believes that better knowledge could help develop safer ways to use cannabis or reduce its harmful effects on lung health.
The complete findings of this research have been published in the American Journal of Respiratory and Critical Care Medicine. The study provides detailed insights into how cannabis smoking changes lung structure and function, offering important information for public health discussions.
These new insights are a step forward in understanding the real impact of cannabis on health, particularly as its use becomes more common around the world.
The study also highlights the need for better education on the risks of smoking cannabis—not just for lung health, but for overall well-being. As more research emerges, it may guide policies that aim to protect public health while accommodating changing attitudes towards cannabis use.
If you care about smoking, please read studies about smoking may increase heart disease risk by 200% and e-cigarette smoke may cause lung cancer and bladder disease.
For more health information, please see recent studies about the cause of weight gain after smoking cessation, and results showing smoking may cause white scars on the brain.
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