Lifestyle factors and plasma biomarkers of Alzheimer's disease: A narrative review.

Alzheimer's disease (AD) is a neurodegenerative disorder characterised by amyloid-β (Aβ), tau hyperphosphorylation and neurodegeneration. Blood-based biomarkers are emerging as a minimally invasive tool for disease detection and monitoring. This review depicts the relationships between modifiable lifestyle factors (nutrition, physical activity (PA), sleep, alcohol consumption, smoking, and social isolation) and plasma biomarkers of AD: Aβ, Aβ, Aβ phosphorylated tau, total tau, neurofilament light chain (NfL) and glial fibrillary acidic protein. Limited evidence suggests that better nutrition is associated with favourable AD plasma biomarker profiles and that PA is associated with less plasma NfL and Aβ, whilst poor sleep is associated with elevated plasma Aβ. However, lack of data and inconsistent findings highlight the need for further investigation to substantiate or refute these trends. Moreover, future research should include the analysis of lifestyle on plasma biomarkers according to gender, metabolic health and APOE status. Considering the growing emphasis on modifiable lifestyle factors for preventing and delaying dementia onset further investigation is justified.