Why some non-smokers get lung disease and some heavy smokers do not

Credit: Myriams-Fotos/Pixabay.

In a recent study, researchers found that people with small airways relative to the size of their lungs may have a lower breathing capacity and, consequently, an increased risk for COPD—even if they don’t smoke or have any other risk factors.

Chronic obstructive pulmonary disease (COPD) is a debilitating lung condition.

It often develops as a result of smoking, but researchers have long puzzled over why nearly a third of cases occur in people who never smoked.

Now they may finally have an answer—and it may be linked to how lungs develop in certain people.

COPD is the fourth leading cause of death in the United States.

It causes airflow blockage and breathing-related problems that can severely limit a person’s day-to-day activities.

Smoking, asthma, or air pollution account for many COPD cases, but up to 30% of cases occur in people who never smoked, and only a minority of heavy smokers develop the disease.

This suggests that there are other risk factors at play.

Previous studies have shown that about half of older adults with COPD appeared to have low lung function early in life.

In the current study, the team examined records for more than 6,500 older adults participating in three studies ((MESA Lung Study, SPIROMICS study, and CanCOLD study) that included smokers and nonsmokers with and without COPD.

Each study assessed dysanapsis with computed tomography (CT) scans of the lungs.

They found that participants with smaller airways relative to lung size were much more likely to develop COPD compared with those with larger airways relative to lung size.

And never smokers with COPD had much smaller airways relative to lung size, whereas the heavy smokers who did not have COPD had larger than normal airways.

The findings suggest that small airways relative to lung size are a very strong risk factor for COPD.

People with larger airways relative to lung size may be able to withstand lung damage from smoking and still have enough breathing reserve to prevent them from developing COPD.

If you care about smoking, please read studies that this stuff in your mouth may increase lung cancer risk, even if you don’t smoke, and findings of why do smoke detector alarms keep going off even when there’s no smoke.

For more information about wellness, please see recent studies about why smokers have a lower risk of COVID-19, and results showing that scientists find the cause of lung cancer in never smokers.

The study was conducted by Benjamin M. Smith et al., and published in JAMA.

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