Biochemical use of neurofilament light polypeptide and vitamin B 12 in relation to diabetic polyneuropathy in Danish adolescents with type 1 diabetes: A cross-sectional study

Abstract

Introduction The aim of this study was to investigate serum Neurofilament Light polypeptide (NfL) as a biomarker for diabetic polyneuropathy (DPN) in adolescents with type 1 diabetes (T1D). Secondarily, to investigate vitamin B 12 (B 12) deficiency as a cause for DPN in adolescents with T1D. Research design and methods Cross-sectional study. Sixty Danish adolescents with T1D (age 15-18 years, diabetes duration >5 years) and 23 age-matched control subjects were included. Based on nerve conduction studies (NCS), intraepidermal nerve fibre density (IENFD) and neurological examination, patients were divided into three groups: (1) T1D without DPN, (2) T1D with subclinical DPN and (3) T1D with confirmed DPN. Blood levels of NfL, B 12, B 12-binding protein holotranscobalamin (HoloTC) and methylmalonic acid (MMA) were determined. Results Twenty-four of the adolescents were without DPN, twenty-one had subclinical DPN and eight had confirmed DPN. NCS was not conducted in three participants and four patients did not have blood samples taken. There were no significant differences in NfL levels or any of the B 12 parameters between any of the groups. Conclusions NfL used in a cross-sectional manner was not found useful to distinguish between the adolescents with DPN and those without. Vitamin B 12 deficiency did not contribute to neuropathy in Danish adolescents with T1D.