Y Chromosome Loss Strongly Associated with Elevated Cardiovascular Disease Risk: Study

As men age, some white blood cells mysteriously lose their Y chromosome—the male sex chromosome. Previously tied to smoking, cancer, and early death, LOY was unclear in healthy hearts. This study asked: does it predict heart attacks specifically?

Researchers analyzed genetic and clinical data from 5,000+ healthy older men in a prevention trial. They measured LOY levels in blood at baseline, then tracked major events (heart attacks, strokes) over 8.4 years. Stats adjusted for smoking, cholesterol, blood pressure, diabetes—everything known. For backup, they cross-checked 190,000+ middle-aged men from a massive biobank.

Findings:

• Nearly 10% suffered major heart events during follow-up

• Each LOY increase = 14% higher heart attack risk

• Men with highest LOY = 68% greater heart attack odds vs. no LOY

• NO stroke link—LOY targets coronary arteries specifically

• Biobank confirmed: even modest LOY raises heart attack risk

Why coronary arteries, not strokes? LOY belongs to clonal haematopoiesis—blood cells mutate with age, pumping out inflammation that clogs heart arteries. Stroke vessels seem more resistant.

Heart disease kills most men globally. LOY offers a simple blood test to spot high-risk guys early, beyond cholesterol checks. While observational (no causality proven), findings held across huge datasets of mostly White males.

This breakthrough reframes aging men's hearts—not just pipes clogging, but blood cells rebelling. Future tests could catch silent LOY before the first chest pain, guiding statins or lifestyle for the invisible chromosome threat lurking in every older man's blood.

REFERENCE: Hussain, S, Bjurling, J, Yu, C. et al. Loss of Y Chromosome and Major Cardiovascular Events in a Prospective Study of Older Men. JACC. 2026 Jan, 87 (1) 36–45.https://doi.org/10.1016/j.jacc.2025.10.069