Examining the relationship between plasma pTau181 and cognitive decline, structural brain integrity, and biological ageing in midlife.
INTRODUCTION: Although plasma pTau181 has been shown to accurately discriminate patients with Alzheimer's disease from healthy older adults, its utility as a preclinical biomarker in middle-aged community-based cohorts is unclear. METHODS: Participants were members of the Dunedin Multidisciplinary Health and Development Study, a longitudinal study of 1037 people born in New Zealand in 1972-1973. Plasma pTau181, MRI-based brain structure, and DunedinPACE (an epigenetic biomarker of biological ageing) were measured at age 45; cognition was measured in childhood and age 45. RESULTS: We observed a wide range of pTau181 concentrations in our same-aged sample (n=856; M=13.6pg/mL, SD=9.1pg/mL). Males had significantly higher pTau181 concentrations than females. No statistically significant associations were observed with cognitive decline, lower structural brain integrity, or accelerated biological ageing. DISCUSSION: In this midlife cohort, wide variation in pTau181 concentrations was present by age 45, but was not associated with patterns of AD-risk in cognition, brain structure, or biological ageing.
