CST3 and stroke disorder: A national cohort analysis utilizing the China Health and Retirement Longitudinal Study (CHARLS) database revealed that participants in the highest cystatin C quartile exhibited a 38% higher risk of stroke morbidity (adjusted OR: 1.38, 95% CI: 1.046–1.825), and Mendelian randomization studies confirmed a causal relationship, demonstrating that genetically predicted cystatin C elevation is associated with a 11% higher stroke risk per standard deviation increase (adjusted OR: 1.128, 95% CI: 1.058–1.203) [21].