Association between serum NfL and cognitive functioning in older adults with diagnosed diabetes: A cross-sectional study from NHANES

Neurofilament light chain (NfL) is a biomarker of neuronal damage that has shown associations with various neurodegenerative conditions, but its relationship with cognitive function in diabetic populations remains understudied. This research investigated the association between serum NfL levels and cognitive performance in individuals with diabetes. Using data from 2013 to 2014 National Health and Nutrition Examination Survey, we conducted a cross-sectional analysis of 179 diabetic participants. Cognitive function was assessed using the digit symbol substitution test, with participants categorized into normal cognitive function (n = 135) and cognitive function decline groups (n = 44). Weighted logistic regression models were employed to examine the relationship between serum NfL and cognitive function. Significant differences in serum NfL levels were observed between the normal cognitive function group (25.84 pg/mL) and the cognitive function decline group (38.63 pg/mL; P = .004). After adjusting for sociodemographic factors, anthropometric measures, comorbidities, and medication use, each unit increase in serum NfL was associated with increased odds of cognitive impairment (odds ratio 1.04, 95% confidence interval: 1.010-1.071, P = .031). A linear association was observed between NfL concentration and the risk of cognitive impairment in diabetic individuals. Robustness of the observed associations was validated through multiple sensitivity analyses. These findings suggest that higher serum NfL levels may be associated with an increased risk of cognitive impairment in diabetic patients, highlighting the need for further research to establish causal relationships and underlying mechanisms.