A new study from Brazil has found that damage to the lungs in younger adults isn’t just caused by smoking.
Obesity and inflammation in the body can also speed up lung aging and may increase the risk of developing chronic lung disease later in life.
The study included nearly 900 people under the age of 40 and was published in the journal BMC Pulmonary Medicine. It found that both obesity and a type of long-term body inflammation, called systemic inflammation, can slowly harm lung function—even in people who don’t smoke.
Chronic obstructive pulmonary disease, or COPD, is often called “smoker’s disease.” It’s a condition that causes swelling and narrowing of the airways, making it hard to breathe. While smoking is still the biggest risk factor for this disease, this new research shows that other factors also play a part.
Researchers followed 895 people born in the city of Ribeirão Preto between 1978 and 1979. Their lung function was measured twice—once when they were around 23 to 25 years old and again when they were 37 to 38 years old. The study looked at how much their lung function had changed over the 12-year period.
The results showed that smoking led to the biggest drop in lung function. On average, smokers lost about 1.95% of lung capacity over the study period. People with higher levels of inflammation in their blood also showed more lung damage.
This inflammation was measured using a marker called C-reactive protein (CRP). For every 1 mg/dL increase in CRP, lung function dropped by 0.76%. Obesity also played a role—each 1 kg/m² increase in body mass index (BMI) led to a 0.28% loss in lung function.
Professor Elcio Oliveira Vianna, who led the study, said that this kind of low-grade inflammation, often seen in obesity, is already known to increase the risk of heart problems. But it also seems to affect the lungs in the long run.
This steady, quiet inflammation can cause lung tissues to age more quickly, even in young people who do not have any diagnosed breathing issues.
The researchers noted signs of early-stage COPD in participants under 40, even though this disease is usually diagnosed later in life. This means that the harmful effects of obesity and body-wide inflammation may start showing up in the lungs much earlier than expected.
Vianna said it’s not common to link obesity with COPD because people with advanced COPD often lose weight due to breathing difficulties. But this study shows that obesity can play a role in starting the disease, even before it shows obvious symptoms.
Dr. Ana Carolina Cunha, the first author of the study and a lung doctor, said the findings give a clearer picture of how complex COPD really is. It’s not just a disease caused by smoking. There can be a mix of genetic, metabolic, and inflammatory factors that put someone at risk.
People with COPD often have ongoing inflammation in the body, which may be a key feature of the disease. This study supports the idea that treating or preventing inflammation—whether it’s caused by smoking, obesity, or other conditions—could be important for protecting lung health.
In short, taking care of your overall health, keeping a healthy weight, and reducing inflammation may help protect your lungs—even if you’ve never smoked.
If you care about lung health, please read studies that many smokers have undetected lung diseases and why vitamin K is very important for you lung health.
For more health information, please read studies about New diabetes drugs can benefit your kidney and lung health and the link between cough and lung cancer.
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