Association between cadmium exposure and serum neurofilament light chain levels: A nationwide population-based survey

Background: Although cadmium exposure had been demonstrated to be toxic to the nervous system, little was known about the link between cadmium exposure and axonal injury. Therefore, the present study aimed to reveal whether there was any correlation between blood cadmium and serum neurofilament light chain (NfL) levels in the general population. Methods: This study included 1040 participants with a median (IQR) age of 47 (35-60) years from the 2013-2014 National Health and Nutrition Examination Survey. Serum NfL levels were measured through immunoassay, and whole blood cadmium concentrations were detected by means of inductively coupled plasma mass spectrometry. Linear regression and restricted cubic spline model was applied to analyze the significance of relationship between blood cadmium and serum NfL levels. Results: In the full adjusted model, blood cadmium levels were found to be positively associated with serum NfL levels (Q4 vs Q1, beta = 3.35, 95 %CI: 0.41, 6.30, p for trend = 0.014). A potential linear positive dose-effect relationship was discovered between blood cadmium and serum NfL levels (p for non-linearity = 0.15). According to the result of stratified analysis, the significant positive relationship between blood cadmium and serum NfL levels was present only in the population of middle-aged and older adults. Conclusion: The present study suggested a positive association between blood cadmium and serum NfL levels in the general US population.