High levels of phenotypic age acceleration (PhenoAgeAccel) were found to have a more significant effect on lung function in patients with chronic obstructive pulmonary disease (COPD), older patients, and White patients.
The researchers explain that COPD is a disease associated with aging, as older patients are more susceptible to it because of how their respiratory system structure and function change with age. However, they also noted that an individual’s actual age does not always reflect their biological senescence.
Instead, a patient’s phenotypic age acceleration (PhenoAgeAccel), which is a patient's phenotype age minus their actual age, helps better assess biological aging rates and identify those at risk for chronic diseases. Consequently, the researchers analyzed the relationship between patients' PhenoAgeAccel, lung function, and COPD.
To create their study population, the researchers used National Health and Nutrition Examination Survey data from between 2007 and 2010 on those 40 years and older. They defined the patients with COPD as those with less than a 0.70 ratio of forced expiratory volume in 1 second to the forced vital capacity (FEV1/FVC) after inhaled bronchodilators. The researchers also calculated each patient’s PhenoAgeAccel, noting that a larger PhenoAgeAccel indicated a higher degree of biological aging.
The study population consisted of 5397 participants, 1042 of whom had COPD; of those with COPD, 48.3% were men amd 49.5% were White, and the average patient age was 54.5 years. Also, patients with COPD had higher rates of comorbid asthma, hypertension, and cardiovascular disease (CVD), as they had higher PhenoAgeAccel values.
The researchers explained that compared with PhenoAgeAccel quartile 1, the baseline quartile, quartiles 3 (OR, 1.39; 95% CI, 1.04-1.86; P = .029) and 4 (OR, 1.52; 95% CI, 1.08-2.14; P = .02) had a 39% and 52% increase in COPD incidence, respectively. Additionally, compared with those with a smoking index less than 10, the researchers found patients with higher PhenoAgeAccel values to have smoking indexes either between 10 and 20 (OR, 1.21; 95% CI, 0.55-1.88; P = .001) or greater than 20 (OR, 1.76; 95% CI, 1.03-2.49; P < .001).
The impact of elevated PhenoAgeAccel values on impaired lung function was felt more by those in the COPD group, those who were older, and those who were White (P for interaction < .05). Also, high PhenoAgeAccel values were associated with cough, sputum, and dyspnea, the researchers noting that “this relationship remained stable in those with normal or not normal lung function.”
The researchers also acknowledged their study’s limitations, one being that it only analyzed patients older than 40 years, meaning the results cannot be generalized to younger patients. Also, they noted that the study only measured data at baseline and more longitudinal data are need to validate the results. Conversely, the researchers explained that their study’s limitations do not minimize their findings.
“These results support the notion that COPD represents an ‘accelerated aging phenotype,’” the authors wrote. “Additionally, we find that a higher smoking index and respiratory symptoms are linked to higher PhenoAgeAccel, emphasizing the importance of smoking cessation and symptom management.”
Ruan Z, Li D, Huang D, et al. Relationship between an ageing measure and chronic obstructive pulmonary disease, lung function: a cross-sectional study of NHANES, 2007–2010. BMJ Open 2023;13:e076746. doi:10.1136/bmjopen-2023-076746