Vitamin D Deficiency And Neurofilament Light Chain (Nfl) As Predictors Of Type 2 Diabetes-Associated Distal Symmetric Polyneuropathy: A Prospective Study

Abstract

Aim: The main aim of this study to evaluate the association of serum vitamin D levels and neurofilament light chain (NFL) concentrations with the presence and severity of Distal symmetric polyneuropathy in patients with type 2 diabetes.

Background:

Distal symmetric polyneuropathy (DSPN) is a common and debilitating complication of type 2 diabetes mellitus (T2DM). Early identification of biomarkers that predict DSPN progression is crucial. This study aimed to evaluate serum 25-hydroxyvitamin D [25(OH)D] and neurofilament light chain (NFL) as predictors of DSPN development and progression over a 3-month follow-up period.

Methods:

A prospective cohort study was conducted on 430 T2DM patients without other causes of neuropathy. Baseline assessments included clinical examination, serum 25(OH)D, NFL levels, and nerve conduction studies. DSPN was diagnosed using the Michigan Neuropathy Screening Instrument (MNSI) and electrophysiological criteria. Participants were followed for 3 months, and changes in DSPN status, NFL, and vitamin D levels were recorded.

Results:

At baseline, 38.1% of participants had DSPN. After 3 months, DSPN prevalence increased to 44.9%. Among vitamin D–deficient individuals, 12.7% developed new DSPN compared to 3.9% in those with sufficient vitamin D (p < 0.001). NFL levels significantly increased in participants with new-onset DSPN (p < 0.001). Multivariate regression showed vitamin D deficiency (OR: 2.38; 95% CI: 1.31–4.33; p = 0.004) and elevated NFL (>40 pg/mL) (OR: 3.14; 95% CI: 1.76–5.59; p < 0.001) were independent predictors of DSPN progression.

Conclusion:

Vitamin D deficiency and elevated NFL levels are significant predictors of DSPN development in T2DM patients over a short-term follow-up. Monitoring these biomarkers may aid in early detection and risk stratification of diabetic neuropathy.