Epigenetic age among US adults with chronic respiratory diseases: results from NHANES 1999–2002

Extract Chronic respiratory diseases affect over 454 million people worldwide and rank as the third leading cause of mortality [1]. Increasing evidence suggests that ageing significantly contributes to their pathogenesis linked to epigenetic changes over the lifespan [2, 3]. DNA methylation markers, which capture gene-environment factors, may underly the development of respiratory diseases and can predict epigenetic ageing rates [2, 4]. Most epigenetic clocks are based on blood DNA methylation, which represents a non-invasive biospecimen as a surrogate of lung ageing [5, 6].