Thyroid Functioning and Fatigue in Women With Functional Somatic Syndromes – Role of Early Life Adversity

Susanne Fischer,Nadine Skoluda,Urs M Nater,Johanna M Doerr,Mattes Kappert,Charlotte Markert,Jana Strahler

doi:10.3389/fphys.2018.00564

Abstract

Objective: Fatigue is a core feature of functional somatic syndromes (FSS). Fatigue is also prominent in patients with thyroid diseases, which is unsurprising given the role of the hypothalamic-pituitary-thyroid (HPT) axis in regulating physiological energy demands. Research in healthy women has shown that early life adversity is linked with alterations in the HPT axis. In view of the substantial prevalence of early life adversity in patients with FSS, our aim was to investigate whether HPT functioning is related to (a) fatigue, and (b) early life adversity in these patients.Methods: N = 33 female patients with FSS and n = 30 age-matched controls were recruited. Fasting morning blood samples were taken to determine thyroid-stimulating hormone (TSH), free triiodothyronine (fT3), and thyroxine (fT4). General, physical, and mental fatigue were measured via the multidimensional fatigue inventory (MFI). Early life adversity was measured using the childhood trauma questionnaire (CTQ).Results: Patients with FSS did not differ from controls in any thyroid parameters (all p > 0.672). However, the lower the patients’ TSH and the higher their fT4, the greater was their general (β = -0.32, p = 0.064; β = 0.35, p = 0.038) and physical (β = -0.47, p = 0.007; β = 0.32, p = 0.077) fatigue. In addition, emotional neglect (β = -0.32, p = 0.057), physical neglect (β = -0.60, p = 0.001), physical abuse (β = -0.47, p = 0.015), and sexual abuse (β = -0.40, p = 0.026) were linked with lower TSH.Conclusion: The lower TSH and the higher fT4, the more fatigue was reported by patients with FSS. In addition, lower TSH was linked with more early life adversity. Larger, prospective studies are warranted to determine whether HPT functioning may be a mediating pathway between early life adversity and fatigue in FSS.

Highlights

Fatigue is a multidimensional phenomenon, which can be described on a physical and mental level
While physical fatigue refers to a state of bodily exhaustion, mental fatigue is characterized by reduced alertness (Smets et al, 1995)
Fatigue is the core symptom of chronic fatigue syndrome (Fukuda et al, 1994), is a case-defining symptom of fibromyalgia syndrome (Wolfe et al, 2010), and is one of the most frequently reported and most distressing symptoms in patients with irritable bowel syndrome, as recently confirmed by meta-analysis (Han and Yang, 2016)

Summary

Introduction

Fatigue is a multidimensional phenomenon, which can be described on a physical and mental level. While physical fatigue refers to a state of bodily exhaustion, mental fatigue is characterized by reduced alertness (Smets et al, 1995). Fatigue is present in several medical diseases, such as cancer (Minton et al, 2013). Around a third of patients seen in primary care report medically unexplained fatigue, that is, fatigue in the absence of such conditions (Steinbrecher et al, 2011). Fatigue features prominently in several of the so-called functional somatic syndromes (FSS), which are characterized by different constellations of physical symptoms that are not attributable to any somatic disease (Wessely et al, 1999). Fatigue is the core symptom of chronic fatigue syndrome (Fukuda et al, 1994), is a case-defining symptom of fibromyalgia syndrome (Wolfe et al, 2010), and is one of the most frequently reported and most distressing symptoms in patients with irritable bowel syndrome, as recently confirmed by meta-analysis (Han and Yang, 2016)

Methods

Results

Conclusion