Loss of the Y chromosome (LOY) is an age-related somatic mutation that is increasingly recognized as a contributing factor to male-specific disease risk. Recent studies have provided growing evidence linking LOY to the development of cardiovascular disease. In this project, we aim to investigate the presence and impact of LOY at single-cell resolution using approximately 250 single-cell RNA sequencing (scRNA-seq) datasets generated with the 10X Genomics platform, within the framework of the Swedish CArdioPulmonary bioImage Study (SCAPIS). By leveraging single cell sequencing, we will explore LOY not only as a blood-based biomarker but also in relation to specific immune cell subsets. This cell-level resolution will enable us to assess LOY as a potential early indicator of conditions such as stroke, chronic obstructive pulmonary disease (COPD), sudden cardiac arrest, myocardial infarction, and other cardiovascular diseases. Contribute to the development of improved methods for risk stratification and personalized prevention strategies in male cardiovascular health, paving the way for preventive interventions before clinical disease onset.