0096 Short sleep duration and poor sleep quality associated with elevated serum NfL and mild cognitive impairment in older Veterans

Abstract

Abstract Introduction Ten percent of adults aged ≥ 65 and 50% of adults ≥ 85 years exhibit cognitive impairment. In addition, 50% of older adults experience poor sleep quality. Veterans are more vulnerable to sleep disturbances and potential cognitive impairment as long-term consequences of on-duty responsibilities, co-morbidities, and conditions such as post-traumatic stress disorder. Previous studies demonstrated a relationship between sleep and cognitive impairment through impaired glymphatic function and neurodegeneration. Biomarkers such as neurofilament light (NfL) are elevated in neurodegeneration and dementia. Here, we sought to investigate NfL levels in cognitive-intact older Veterans exhibiting poor sleep quality. Methods A cross-sectional study with eighteen Veterans aged 65-86 without a clinical diagnosis of dementia. Self-reported sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI), while time in bed (TIB), and total sleep time (TST) were retrieved from Fitbit Charge. Cognitive function was evaluated with the St. Louis University Mental Status Exam (VA-SLUMS). We used an automated multiplex immunoassay system to identify dementia biomarkers using an enzyme-linked lectin assay. T-tests, one-way or two-way ANOVAs with Tukey’s post-hoc (with or without repeated measures) were used for the analysis. Results Participants were classified as good sleepers (PSQI>5) and poor sleepers (PSQI< 5). Poor sleepers spent less TIB (Fitbit 5.3h vs. 7.7h, p =0.001) and slept fewer hours (Fitbit 4.7h vs. 7.2h, p =0.001) when compared to good sleepers. Additionally, poor sleepers exhibited mild cognitive impairment (VA SLUMS 26.9, p, =0.01). Lastly, poor sleepers exhibited higher serum NfL (mean 66.7, p=0.04). Conclusion Poor sleep quality was associated with short sleep duration, mild cognitive impairment, and higher serum levels of NfL in older Veterans without a dementia diagnosis. Results may contribute to the early identification of dementia and sleep-centered treatment guidance. Further studies with more extensive and diverse samples are warranted before clinical recommendations. Support (if any) Carleara Weiss, Ph.D., MS, RN. 1K99AG079117-01 (PI), National Institute on Aging.