Association of soluble tumor necrosis factor receptor 1 with tau pathology, brain atrophy, and cognitive decline: a longitudinal study.

backgroundWe tested whether inflammation indexed by soluble tumor necrosis factor receptor-1 (sTNFR1) is related to cognitive decline. We examined serum sTNFR1 with cognition in the Health and Retirement Study (HRS) and cerebrospinal fluid (CSF) sTNFR1 with tau pathology and magnetic resonance imaging (MRI)-based atrophy in the Alzheimer's Disease Neuroimaging Initiative (ADNI). Finally, we used Mendelian randomization (MR) to assess associations between genetically proxied sTNFR1 and regional brain volumes.

methodsData were from HRS (2016-2020; N = 6028) and ADNI (N = 287). In HRS, serum sTNFR1 was log-transformed (quartiles); in ADNI, CSF sTNFR1 was analyzed. Global cognition included word recall, serial 7 s, and counting backwards. In ADNI, cognition was measured by the Clinical Dementia Rating-Sum of Boxes (CDR-SB); CSF total tau/phosphorylated tau and longitudinal MRI regional volumes were analyzed. Associations were estimated with linear and linear mixed-effects models adjusted for demographic, clinical, and genetic covariates including apolipoprotein E ε4 (APOE ε4). Incident mild cognitive impairment (MCI)/dementia was modeled with cause-specific Cox and Fine-Gray models. Incremental prediction used optimism-corrected change in area under the curve (AUC; ΔAUC), net reclassification improvement (NRI)/integrated discrimination improvement (IDI), calibration, and decision curve analysis. MR used genome-wide association study (GWAS) statistics to test effects of genetically proxied sTNFR1 on MRI-derived regional volumes.

resultsIn HRS (follow-up 4 years), higher serum sTNFR1 was associated with lower baseline cognition and faster decline in global cognition (β = - 0.16/year). Higher sTNFR1 predicted MCI/dementia (Cox HR ≈ 1.17; Fine-Gray sHR ≈ 1.14); among cognitively normal individuals, risk was elevated (OR = 1.30; 95% CI, 1.03-1.63). Adding sTNFR1 to 2- and 4-year prediction models conferred small discrimination gains after internal validation (ΔAUC ≤ 0.003) and minimal or inconsistent net clinical benefit. In ADNI, higher CSF sTNFR1 was associated with greater CSF total tau and phosphorylated tau, and predicted accelerated caudate atrophy. Exploratory MR suggested a nominal association with reduced right inferior temporal volume, limited by instruments.

conclusionssTNFR1 is associated with cognitive decline and tau-related selective neurodegeneration, but provides limited incremental predictive value beyond established risk factors; external validation and replication are warranted.