Subjective aging and neurobiomarkers of brain health in the health and retirement study.

BACKGROUND: Subjective aging, operationalized by subjective age and self-perceptions of aging (SPA), has been consistently associated with cognition and incident dementia. The present study examined the association between subjective aging and blood neurobiomarkers of brain health. METHODS: Participants (N = 3401; 59% female, Mean Age= 68.17, SD= 9.76) were from the Health and Retirement Study. Four neurobiomarkers were assessed in 2016 using the Simoa immunoassays: the amyloid-β 42 to 40 ratio (Aβ42/Aβ40 ratio), phosphorylated tau-181 (p-tau181), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP). Subjective age, SPA, and demographic, clinical, behavioral, and psychological covariates were obtained in 2014/2016. RESULTS: Controlling for demographic factors, an older subjective age (β=.07, p<.001) and negative SPA (β=.06, p<.001) were associated with higher NfL. Subjective age and SPA were unrelated to GFAP, Aβ42/Aβ40 ratio, and p-tau181. The link between an older subjective age and NfL persisted adjusting for clinical, behavioral, and psychological factors. The associations between subjective aging and neurobiomarkers were not moderated by age, sex, cognitive status, APOE status, or wave of assessment. CONCLUSION: The present study found novel evidence that an older subjective age and negative SPA were related to neuroaxonal injury. This study points to a potential neuropathological pathway linking subjective aging to brain health.