Article type: Original Clinical Research

Yingming Kong ^1,2 Yanghao Tai ^1,2 Bin Chen ^1,2 Chunzheng Li ² Hao Chen ^1,2,3* Liang Shi ^1,2,3*

• ¹ Third Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences Tongji Shanxi Hospital, Taiyuan, 030032, China, Taiyuan, Shanxi Province, China
• ² Shanxi Medical University, Taiyuan, Shanxi Province, China
• ³ Department of Neurology, Shanxi Bethune Hospital, Shanxi Academy of Medical Science, Tongji Shanxi Hospital, Third Hospital of Shanxi Medical University, Taiyuan, 030032, China, Taiyuan, China

Objective Serum neurofilament light chain (sNfL) is one of the most sensitive diagnostic biomarkers for a variety of neurodegenerative pathologies. Potassium, an essential electrolyte, plays a critical role in maintaining neuronal health and the proper functioning of the central nervous system (CNS). The aim of our research was to investigate the association between serum potassium level and sNfL levels.Methods Based on the National Health and Nutrition Examination Survey (NHANES) database, we analyzed data from the 2013-2014 NHANES. Serum potassium concentrations were measured via ion-selective electrode (ISE) technology. The levels of sNfL were measured using a sensitive immunoassay developed by Siemens Healthineers. Our researcher analyzed the association between potassium level in serum and sNfL in American persons using multivariate logistic regression analysis and smoothed curve fitting. The consistency of these results was examined in various population subgroups.ResultsA total of 1670 participants were involved in our research, including 872 women (50.5%) and 798 men (49.5%). The median serum potassium concentration was 4.0 mmol/L and the median sNfL was 12.3 pg/mL. After adjusting for potential confounders in the full model, individuals with higher serum potassium concentrations had higher sNfL levels (Q3 vs. Q1，β = 2.86, 95% CI：0.33-5.39，p = 0.027）. There was a nonlinear positive dose-response association between higher serum potassium concentrations and sNfL levels (P for nonlinearity = 0.028). Based on the results of stratified analysis, the relationship was stronger in the low- and middle-income group, non-drinking and non-physical activity participants, and participants with hypertension and diabetes.Interpretation In the cohort of American adults, a greater serum potassium concentration was linked to a higher sNfL. However, causality still needs to be further verified.