Mosaic Loss of Y chromosome associates with lung function, emphysema and epigenetic aging

Rationale As the global population ages, identifying risk factors for age-related diseases, such as COPD, is crucial for public health. Mosaic loss of Y chromosome (mLOY) in blood cells is an age-related somatic mosaicism event, but its relationship with pulmonary health remains undercharacterized. Objectives To examine the association between mLOY and pulmonary outcomes in men. Methods Leveraging mLOY assessment (cell fraction ≥ 5%) in over 12,000 men, including 5,097 from the COPDGene Study and 7,235 from six additional cohorts in the Trans-Omics for Precision Medicine program, we investigated mLOY associations with respiratory outcomes and epigenetic aging using multivariable cross-sectional, longitudinal, and prospective models. Primary outcomes included spirometry, CT-based emphysema, and epigenetic pace of aging. Results The prevalence of mLOY increased with age. Cross-sectionally, mLOY was associated with airflow obstruction, with reduced FEV1/FVC of 0.018 [95% CI -0.030, -0.006] in COPDGene and 0.020 [95% CI -0.027, -0.013] in TOPMed. mLOY was also associated with greater CT-quantified lung emphysema and faster pace epigenetic aging. Longitudinally, mLOY was associated with faster FEV1 decline (∼55mL/year vs ∼38mL/year). Prospectively, mLOY was associated with higher odds of developing COPD [OR = 1.84, 95% CI 1.10, 3.07] and PRISm [OR = 2.87, 95% CI 1.09, 7.56] among participants with normal lung function at baseline. Associations remained robust after adjusting for clonal hematopoiesis and telomere length. Conclusions mLOY is associated with lower lung function, accelerated lung function decline, higher emphysema, and faster pace of aging, positioning mLOY as a potential biomarker of respiratory aging in men.