Many people now see cannabis as a safer and more natural option than cigarettes. As more countries and states legalize marijuana for medical or recreational use, its popularity continues to grow.
Smoking, vaping, and dabbing cannabis have become common among adults, especially younger people who may believe it causes little or no long-term harm.
However, a major new study suggests that breathing cannabis smoke or vapor into the lungs every day may increase the risk of serious breathing problems, including asthma and chronic lung disease.
The research was published in the Journal of General Internal Medicine by scientists at the University of California, San Francisco (UCSF). The team wanted to better understand how cannabis affects the lungs, especially in people who do not smoke tobacco.
For many years, doctors and researchers have clearly warned people about the dangers of cigarette smoking. Cigarettes are strongly linked to lung cancer, heart disease, chronic obstructive pulmonary disease, also known as COPD, and many other illnesses.
But cannabis has not been studied nearly as much, even though millions of people now use it regularly.
One reason for the lack of research is that cannabis remained illegal in many places for decades, making large health studies difficult. At the same time, the image of cannabis in society has changed quickly.
Many people believe marijuana is less harmful than tobacco because it comes from a plant and is often promoted as natural. Some users also turn to vaping or dabbing because they think these methods are cleaner than smoking.
However, the lungs are still exposed to heated chemicals, smoke, or vapor that may irritate and damage delicate lung tissue over time.
To investigate the issue, the UCSF researchers studied health information from nearly 380,000 adults across the United States.
The data came from the Behavioral Risk Factor Surveillance System, a large health survey run by the U.S. Centers for Disease Control and Prevention, also known as the CDC. The survey collects information about people’s health habits, medical conditions, and lifestyle choices.
Importantly, more than 222,000 people in the study had never smoked cigarettes. This allowed researchers to separate the effects of cannabis from the well-known damage caused by tobacco. The study became one of the largest investigations ever focused on cannabis inhalation and lung health among non-tobacco users.
The researchers looked at people who inhaled cannabis in different ways. This included smoking marijuana, using electronic vaping devices, and dabbing, which involves breathing in strong cannabis concentrates heated into vapor. All of these methods send substances directly into the lungs.
The results were worrying. People who inhaled cannabis every day had a 44 percent greater risk of developing asthma compared with people who did not use cannabis.
Asthma is a condition that causes swelling and narrowing of the airways, making it difficult to breathe. It can lead to coughing, wheezing, chest tightness, and shortness of breath. Asthma attacks can sometimes become severe and dangerous.
The researchers also found that daily cannabis users had a 27 percent greater chance of developing chronic obstructive pulmonary disease, or COPD. COPD is a serious long-term lung disease that makes breathing increasingly difficult over time.
It includes conditions such as chronic bronchitis and emphysema. Many people with COPD struggle with constant coughing, mucus production, tiredness, and reduced ability to exercise or do daily activities.
The risk appeared even stronger in people who had never smoked tobacco. Among non-smokers, daily cannabis inhalation was linked to a 51 percent higher likelihood of developing asthma.
Although the increase in COPD risk among non-smokers was not considered statistically strong enough to be fully confirmed, researchers still saw signs that cannabis could contribute to long-term lung damage.
The scientists noted that the real COPD risk may actually be higher than what the study found. COPD usually develops slowly over many years or even decades.
Because cannabis legalization and widespread use are still relatively recent in many parts of the United States, researchers may not yet be seeing the full long-term impact on lung health.
Dr. Alison Rustagi, the lead author of the study and an assistant professor at UCSF, said public understanding of cannabis risks remains unclear.
She explained that decades of public health campaigns have successfully educated people about the dangers of tobacco smoking, but many people still do not realize that inhaling cannabis may also harm the lungs.
The study does not claim that every form of cannabis use is equally dangerous. Instead, it highlights that frequent inhalation, especially daily use, may carry significant health risks. Experts say the findings should encourage people to think more carefully about how often they use cannabis and how they consume it.
As cannabis becomes more accepted socially and legally, scientists say it is important for the public to receive balanced information about both possible benefits and possible harms.
While cannabis may help some patients with medical conditions such as chronic pain or nausea, researchers stress that people should not assume inhaling it is harmless simply because it is legal or widely used.
The study adds to growing evidence that the lungs may react negatively to repeated exposure to cannabis smoke and vapor. Researchers hope future studies will continue exploring the long-term effects, especially as cannabis use continues to rise worldwide.
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