Blood Metal Signatures and Their Association with Alzheimer’s Disease Risk and Cognitive Decline in an Egyptian Cohort

This project investigates the role of environmental metal exposure in Alzheimer’s disease (AD) within an understudied Egyptian population, addressing a critical gap in region-specific dementia research. Using a cross-sectional case–control design, we quantified blood concentrations of arsenic, lead, mercury, and lithium in 50 clinically diagnosed AD patients and 50 cognitively healthy controls. Advanced statistical approaches were applied to account for left-censored data and detection limits. The study identified significantly elevated arsenic and lead levels in AD patients, with arsenic demonstrating a strong independent association with increased AD risk after adjustment for age and sex. Lithium levels were lower among AD cases and showed an inverse association with disease status, suggesting a potential protective effect, while mercury findings were constrained by detection limitations. Collectively, this work provides evidence supporting the contribution of toxic metal exposure to AD risk and highlights lithium as a candidate protective factor, reinforcing the importance of integrating environmental determinants into dementia research and prevention strategies in low- and middle-income countries.