title: Circadian cortisol and fatigue severity in relapsing-remitting multiple sclerosis.
abstract: Cortisol is a key regulator of the immune system, energy metabolism, and stress, yet its relevance to fatigue experienced by people with relapsing-remitting multiple sclerosis (RRMS) remains uncertain. We examined cortisol secretory activity in RRMS and its association with fatigue severity between-individuals and within-individuals (day-to-day) using a case-control ecological momentary assessment design. While undergoing usual daily routines, 38 people with RRMS and 38 healthy control participants provided saliva samples at strategic time-points over 4 consecutive weekdays to measure the cortisol awakening response (CAR; 0, 30, and 45 min after awakening) and the diurnal cortisol slope (DCS; 6 quasi-random samples provided between 1000 h and 2000 h). Recalled fatigue was measured at baseline, and daily fatigue was measured as the mean average of momentary fatigue ratings provided alongside each DCS sample. Multilevel modeling found CAR output was greater in RRMS than controls, and recalled fatigue in RRMS was associated with both lower waking cortisol level and larger awakening response. Day-to-day, the CAR was not associated with same-day fatigue levels in RRMS. Cortisol appears to have a role in fatigue experienced in RRMS, but whether it is a causal factor remains unclear.
authors: Aberdeen Health Psychology Group, Institute of Applied Health Science, University of Aberdeen, AB25 2ZD, UK; Psychology, Faculty of Social and Human Sciences, University of Southampton, SO17 1BJ, UK. Electronic address: daniel.powell@abdn.ac.uk.
authors: Daniel J H
authors: DJ
authors: Powell
authors: Psychology, Faculty of Social and Human Sciences, University of Southampton, SO17 1BJ, UK; Health Psychology Section, Institute of Psychiatry, King's College London, London SE1 9RT, UK.
authors: Rona
authors: R
authors: Moss-Morris
authors: Psychology, Faculty of Social and Human Sciences, University of Southampton, SO17 1BJ, UK.
authors: Christina
authors: C
authors: Liossi
authors: Psychology, Faculty of Social and Human Sciences, University of Southampton, SO17 1BJ, UK; Max Planck Institute of Empirical Aesthetics, 60322 Frankfurt am Main, Germany.
authors: Wolff
authors: W
authors: Schlotz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002940:Circadian Rhythm; D003863:Depression / Q000209:etiology / Q000523:psychology; D004185:Disability Evaluation; D005221:Fatigue / Q000209:etiology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000097:blood* / Q000503:physiopathology* / Q000523:psychology; D009422:Nervous System Diseases / Q000503:physiopathology; D011597:Psychomotor Performance; D057566:Self Report; D055815:Young Adult
chemical_list: D006854:Hydrocortisone
keywords: Cortisol; Fatigue; Hypothalamic–pituitary–adrenal axis; Multiple sclerosis