The impact of kidney function on plasma neurofilament light and phospho-tau 181 in a community-based cohort: the Shanghai Aging Study

Background The blood-based biomarkers are approaching the clinical practice of Alzheimer’s disease (AD). Chronic kidney disease (CKD) has a potential confounding effect on peripheral protein levels. It is essential to characterize the impact of renal function on AD markers. Methods Plasma phospho-tau181 (P-tau181), and neurofilament light (NfL) were assayed via the Simoa HD-X platform in 1189 dementia-free participants from the Shanghai Aging Study (SAS). The estimated glomerular filter rate (eGFR) was calculated. The association between renal function and blood NfL, P-tau181 was analyzed. An analysis of interactions between various demographic and comorbid factors and eGFR was conducted. Results The eGFR levels were negatively associated with plasma concentrations of NfL and P-tau181 ( B = − 0.19, 95% CI − 0.224 to − 0.156, P < 0.001; B = − 0.009, 95% CI − 0.013 to -0.005, P < 0.001, respectively). After adjusting for demographic characteristics and comorbid diseases, eGFR remained significantly correlated with plasma NfL ( B = − 0.010, 95% CI − 0.133 to − 0.068, P < 0.001), but not with P-tau181 ( B = − 0.003, 95% CI − 0.007 to 0.001, P = 0.194). A significant interaction between age and eGFR was found for plasma NfL ( P interaction < 0.001). In participants ≥ 70 years and with eGFR < 60 ml/min/1.73 m 2 , the correlation between eGFR and plasma NfL was significantly remarkable ( B = − 0.790, 95% CI − 1.026 to − 0,554, P < 0.001). Conclusions Considering renal function and age is crucial when interpreting AD biomarkers in the general aging population.