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Melatonin is a biomarker of circadian dysregulation and is correlated with major depression and fibromyalgia symptom severity

Authors Caumo W, Hidalgo MP, Souza A, Torres ILS, Antunes LC

Received 13 June 2018

Accepted for publication 5 November 2018

Published 31 January 2019 Volume 2019:12 Pages 545—556


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Dr Michael A Überall

Wolnei Caumo,1–3 Maria Paz Hidalgo,4,5 Andressa Souza,6 Iraci LS Torres,1,7 Luciana C Antunes8

1School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil; 2Pain and Palliative Care Service at Hospital de Clínicas de Porto Alegre (HCPA), Laboratory of Pain and Neuromodulation at UFRGS, Porto Alegre, Brazil; 3Pain and Anesthesia in Surgery Department, School of Medicine, UFRGS, Porto Alegre, Brazil; 4Psychiatry Department, School of Medicine, UFRGS, Porto Alegre, Brazil; 5Laboratorio de Cronobiologia e Sono do Hospital de Clinicas de Porto Alegre; Porto Alegre, Brazil; 6Postgraduate Program in Health and Human Development, La Salle Universitary Center, Canoas, Brazil; 7Pharmacology Department, Instituto de Ciências Básicas da Saúde, UFRGS, Porto Alegre, Brazil; 8Centro de Ciências da Saúde – Departamento de Nutrição da Universidade Federal De Santa Catarina, Florianopolis, Brazil

Objective: This study compared urinary 6-sulfatoxymelatonin (aMT6s) over 24 hours among fibromyalgia (FM), major depression disorder (MDD), and healthy control (HC) groups, and examined whether rhythm is correlated with depressive symptoms. To answer this question we compared the rhythm of urinary aMT6s secretion among each group in four time series: morning (06:00–12:00 hours), afternoon (12:00–18:00 hours), evening (18:00–24:00 hours), and night (24:00–06:00 hours). In the FM subjects, we assessed if the rhythm of urinary aMT6s secretion is associated with pain severity, sleep quality, number of trigger points (NTPs), and the pain pressure threshold (PPT).
Patients and methods: We included 54 women, aged 18–60 years with diagnosis of FM (n=18), MDD (n=19), and HC (n =17). The 24-hour urinary aMT6s was evaluated according to four standardized periods. The assessment instruments were the Hamilton Depression Rating Scale (HDRS), Pittsburgh Sleep Quality Index, and Fibromyalgia Impact Questionnaire.
Results: A generalized estimating equation revealed no difference in the daily load of aMT6s secretion among the three groups (P=0.49). However, at the daily time (06:00–18:00 hours), the load secretion of aMT6s reached 41.54% and 60.71% in the FM and MDD, respectively, as compared to 20.73% in the HC (P<0.05). A higher score in the HDRS was positively correlated with the amount of aMT6s secretion during daytime (06:00–18:00 hours). Also, multivariate linear regression revealed that in FM subjects, the aMT6s secretion during daytime (06:00–18:00 hours) was negatively correlated with the PPTlog (partial η2=0.531, P=0.001). However, it was positively correlated with depressive symptoms (partial η2=0.317, P=0.01); PQSI (partial η2=0.306, P=0.017), and NTPs (partial η2=0.23, P=0.04).
Conclusion: A more significant load of aMT6s secretion during daytime hours was observed in MDD and FM subjects compared to HC. These findings help to comprehend the biological basis of these disorders and show how disruption in melatonin secretion is positively correlated with clinical symptoms.

Keywords: fibromyalgia, depression, pain, melatonin, 6 sulfatoxymelatonin (aMT6s).

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