The researchers found that the low-grade systemic inflammation characteristic of obesity contributes to lung tissue damage over time (photo by Engin Akyurt on Unsplash)
Published on 12/15/2025
By Maria Fernanda Ziegler | Agência FAPESP – A Brazilian study involving nearly 900 participants under the age of 40 reinforces the idea that premature lung aging is linked not only to smoking but also to factors such as obesity and systemic inflammation. These two conditions may even be associated with an increased risk of developing chronic obstructive pulmonary disease (COPD).
Also known as “smoker’s disease,” COPD is an irreversible condition characterized by inflammation and thickening of the airways. This leads to shortness of breath, difficulty breathing, and other progressive limitations. Although smoking remains the main risk factor, the study suggests that obesity and systemic inflammation alone can lead to lung deterioration.
According to the results of the study, smoking has the greatest impact and is associated with an average reduction of 1.95% in lung function over the 12 years analyzed. Systemic inflammation, measured by C-reactive protein (CRP) levels in the blood, was also associated with lung function decline. Each 1 mg/dL increase in CRP corresponded to a 0.76% decline in lung function. In cases of obesity, each 1 kg/m² increase in body mass index (BMI) resulted in an additional 0.28% loss in lung function.
The study, published in the journal BMC Pulmonary Medicine and supported by FAPESP, contributes to a broader understanding of the different pathways that can lead to loss of lung function.
The researchers included 895 participants from the Ribeirão Preto Birth Cohort, which follows individuals born between 1978 and 1979, in the study. The participants’ lung function was measured at two points in time: once between the ages of 23 and 25 and again between the ages of 37 and 38.
“The findings reinforce what previous studies with smaller cohorts had already shown: in addition to the effects of smoking, systemic metabolic and inflammatory processes can play an important role in the deterioration of lung function, even in younger individuals without diagnosed respiratory diseases,” says Elcio Oliveira Vianna, a professor at the Ribeirão Preto School of Medicine at the University of São Paulo (FMRP-USP) and coordinator of the study.
Vianna explains that according to the study, systemic inflammation originating in other organs or parts of the body, such as adipocyte inflammation in cases of obesity, can interfere with the lungs. “Low-grade systemic inflammation, already known to increase the risk of cardiovascular disease, also affects and damages the lungs. This constant inflammatory bombardment, even if subtle, as in the case of obesity, contributes to lung tissue damage over time and can trigger premature lung aging,” Vianna explains.
COPD, a multifactorial disease
Although the cohort participants were under 40 years of age at the time of examination and therefore outside the typical age range for COPD diagnosis, the researchers observed early signs of the disease. This allowed them to infer that obesity and systemic inflammation increase the risk of developing COPD in the future.
“Systemic inflammation has a direct impact on lung function, and we were able to demonstrate that in this population study. As all participants were young, it was possible to identify signs of the disease even before its clinical diagnosis,” says Vianna.
However, he points out that associating COPD with obesity is uncommon. “Among the consequences of COPD are loss of appetite and high caloric expenditure [loss of fat and lean mass] due to the effort required to breathe. Therefore, since COPD patients are usually thin, it’s uncommon to associate the disease with obesity. That’s why it was important for our study to demonstrate that, like other systemic inflammations, it can trigger the disease,” he says.
For Ana Carolina Cunha, a pulmonologist and the first author of the study, the results help broaden our understanding of the complexity of COPD. “The disease is multifactorial and much more complex than previously thought. In addition to the inflammation caused by smoking, there may be a systemic inflammatory process specific to the individual. Previous studies have already pointed to this association. Today, we know that COPD patients have chronic inflammation, raising the hypothesis that this process may be a common factor among different manifestations of the disease, especially in people with a genetic or metabolic predisposition.”
The article “Longitudinal study of the influence of obesity, C-reactive protein, and smoking on FEV1 decline in young adulthood” can be read at bmcpulmmed.biomedcentral.com/articles/10.1186/s12890-025-03913-5.
Source: https://agencia.fapesp.br/56824
