Thirty years after anorexia nervosa onset, serum neurofilament light chain protein concentration indicates neuronal injury

Henrik Zetterberg,Kaj Blennow,Christopher Gillberg,Carina Gillberg,Elisabet Wentz,Lisa Dinkler,Maria Råstam,Sandra Rydberg Dobrescu

doi:10.1007/s00787-020-01657-7

Abstract

Little is known about the long-term consequences of anorexia nervosa (AN) in terms of possible brain neuronal injury. We aimed at investigating whether women with adolescent-onset AN exhibit increased serum levels of neurofilament light chain protein (NfL), a biomarker for neuronal injury, compared with matched controls at 30-year follow-up. Blood samples were collected from 34 women with adolescent-onset AN and 38 matched healthy comparison women (COMP), at a mean age of 44 years (range 38–48 years). NfL was measured in serum using the in-house single molecule array (Simoa) method. The individuals were asked whether they or their parents had been diagnosed with dementia. The Swedish National Patient Register was searched for diagnoses related to dementia. Serum NfL concentrations were significantly higher in the AN group (AN 27.7 pg/ml; COMP 19.0 pg/ml; p = 0.041). When individuals with medical/neurological disorders in the AN and COMP groups were excluded, there was a statistically non-significant trend towards higher concentrations in the AN group (AN 27.4 pg/ml; COMP 18.8 pg/ml; p = 0.060). None of the participants had been diagnosed with dementia. There was no significant correlation between serum NfL and AN duration (r = 0.15). There was a moderate negative correlation between the serum NfL concentration and the current BMI in the AN group (r = 0.44). This is the first time that serum NfL has been assessed in middle-aged women with a history of adolescent-onset AN. The results suggest that there might be increased axonal degeneration as a sequel of AN. Individuals remaining underweight had higher serum NfL concentrations than those with a normal/high BMI. Additional studies are needed to confirm increased serum NfL concentrations in individuals recovered from AN. There is a need for further study of axonal degeneration as a consequence of AN.

Highlights

Anorexia nervosa (AN) is a severe psychiatric disorder that mainly affects adolescent and young adult females and has its peak onset in adolescence
A dropout analysis regarding participants who declined the collection of blood samples at the 30-year follow-up (AN n = 13; comparison women (COMP) n = 10) showed no significant differences between participants and dropouts in terms of age, body mass index (BMI), Global Assessment of Functioning scale (GAF), Morgan Russell averaged scale score, full eating disorders (EDs) symptom recovery and AN duration at the 30-year follow-up
The serum neurofilament light chain protein (NfL) concentrations were significantly higher in the AN group compared with the COMP group (p = 0.041) (Table 2; Fig. 1)

Summary

Introduction

Anorexia nervosa (AN) is a severe psychiatric disorder that mainly affects adolescent and young adult females and has its peak onset in adolescence. The mean duration of AN is approximately 5 years. The crossover rate into other eating disorders (EDs) is high, and the mean duration of all aggregated ED episodes, including AN, is estimated to be 10 years [1]. Reduced brain volume in AN was first observed in postmortem studies in the 1950s [2]. The brain atrophy was later corroborated using neuroimaging techniques and the findings included prominent sulci and gyri, enlarged ventricles, and reduced cerebral mass affecting both white and grey matter volume [3, 4]. According to a review from 2018, the volume deficits seem to be largely reversible in remitted adult cases of AN, while the data regarding adolescent AN cases are inconclusive [5]

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Conclusion