Epigenetic Age Associations with Chronic Obstructive Pulmonary Morbidity and Severity

Individuals with Chronic Obstructive Pulmonary Disease (COPD) experience increased morbidity and mortality due to acute worsening of respiratory symptoms. A growing body of evidence suggests the aging pathway is implicated in both COPD risk and COPD-related phenotypes. Identifying the role aging plays in lung function, severity, morbidity, and quality of life in COPD patients could inform potential avenues for treatment. Additionally, understanding how socio-economic position and demographic characteristics might modify aging pathways could inform opportunities to address disparities in COPD. This study aims to identify whether subpopulations may be at most risk for COPD-related outcomes due to epigenetic aging in a diverse and low-income sample of COPD patients. Epigenetic clocks capture methylation at loci across the epigenome that are predictive of age. We estimated epigenetic age using the Horvath epigenetic clock and examined how divergences of epigenetic age from biological age were related to quantitative measures of lung function, COPD severity, morbidity, and quality of life in a low-income and racially diverse COPD population. Multivariable linear regression models adjusting for sex, continuous hospital anxiety and depression scale, baseline pack-years, European American race, and continuous baseline body mass index reveal null relationships between epigenetic aging and lung function or questionnaires measuring severity, morbidity, and quality of life. We also tested for effect measure modification of aging relationships by sex, income, and race. We observed significant effect measure modification for the relationship between increasingly better lung function categories and intrinsic epigenetic aging by income, dichotomized at a $20,000 threshold (p = 0.02). Individuals with incomes above $20,000 per year exhibited age deceleration with increasingly better lung function (p = 0.03). This result may indicate that the epigenetic aging pathway plays differential roles in lung function depending on income group