Fatigue: Biomedicine, Health & Behavior - Volume 6, Issue 3, 2018

Volume 6, Issue 3, 2018

 * Mitochondrial DNA copy number is not associated with fatigue status in Primary Sjögren’s Syndrome"Abstract - Background: Primary Sjögren’s syndrome (pSS) is a heterogeneous disease characterized by lymphocytic infiltrates to the exocrine glands, causing sicca symptoms and other manifestations. Fatigue is one of the most prominent symptom in pSS; up to 70% suffer from chronic fatigue. Fatigue has been shown to be common and severe in patients suffering from primary mitochondrial DNA (mtDNA) disease. In a number of chronic diseases, mitochondrial DNA copy number (mtDNAcn) has been reported to be altered.""Purpose: The aim of the study was to examine if mtDNAcn was altered in fatigued versus non-fatigued pSS.""Methods: We quantified mtDNAcn using quantitative polymerase chain reaction (qPCR) with mitochondrial ND2 as a target gene normalized to nuclear HβB (mtDNA:nDNA).""Results: In 204 participants, 108 fatigued and 96 non-fatigued, relative mtDNAcn did not distinguish fatigue status (p = 0.7) nor was it correlated with severity of fatigue (p = 0.21).""Conclusion: MtDNAcn is not altered with fatigue status in blood in pSS. Our analysis suggests that when conducting mtDNAcn analysis with large sample numbers over multiple days a two-way-ANOVA should be used in preference to a one-way-ANOVA or t-test to allow detection of batch effects."


 * Double-blinded placebo-controlled cross-over pilot trial of naltrexone to treat Gulf War Illness"Abstract - Background: 30% of Gulf War veterans developed Gulf War Illness (GWI) with chronic fatigue, pain, and neuropsychological disabilities.""Purpose: To assess the efficacy of low-dose naltrexone to treat GWI.""Methods: A double-blinded, placebo-controlled crossover trial of naltrexone 4.5 mg/day was conducted. The Clinical global impression scale (CGIS), visual analogue scales (VAS), SF-36 Health Survey, and the Connors Continuous Performance Test assessed treatment response. ClinicalTrials.gov registry Identifier is NCT02206490. Results: Thirty-seven participants completed the protocol. 100% had upper airway inflammation on examination. 88% were overweight or obese. The CGIS detected improvement in 38% of patients (n = 14) (responders), with 6 of these patients reporting much improvement. Non-responders were rated as showing no change from baseline (n = 18; 49%), or were rated minimally worse (n = 5; 13%). On the SF-36 Health Survey, responders showed significantly less disability than non-responders with respect to emotional limitations (p = 0.01) as well as greater improvement on VAS scales for confusion (p < 0.01), vertigo (p = 0.03) and depression (p = 0.05). All enrolled participants had detectable levels of naltrexone in their serum at the end of the treatment period, with values ranging from 1.5to 18 ng/ml. Anecdotally, some subjects and their spouses felt that naltrexone should be continued after the study ended." Conclusions: This pilot trial suggests low-dose naltrexone may be effective for some with GWI. Further study and consideration of other doses is needed.


 * Liver volume is lower and associates with resting and dynamic blood pressure variability in chronic fatigue syndrome"Abstract - Background: Chronic fatigue syndrome (CFS) in many cases is characterised by abnormal autonomic function and lower blood pressure (BP). In animals the liver is a capacitance vessel for BP homeostasis. We developed a novel liver magnetic resonance (MR) imaging technique to compare liver volume in CFS to controls, and to explore its role in cardiovascular physiology.""Methods: Liver MR (single breath-hold, enhanced T1-weighted, high-resolution isotropic volume excitation 3-Tesla Achieva, NL) determined liver volume. Red cell and plasma volume were also measured. A 10 min resting cardiac autonomic assessment using beat-to-beat measurement (Taskforce; CNSystems) was followed by assessment of hemodynamic response to standing to determine blood pressure drop and return to baseline.""Results: Forty-four CFS patients (age = 45.5, 34f/10 m, Fukuda criteria) and 10 age, activity and sex matched controls (age = 49.4, 7f/3 m) participated. Adjusted for body size, CFS patients had significantly reduced liver volumes (775 (101) ml/m2 v 846 (96) ml/m2; p = 0.02). At rest, liver volume was unrelated to symptom severity, heart rate, BP or heart rate variability. Both increased systolic and diastolic low frequency (LF) BP variability (predominantly sympathetic) were associated with lower liver volumes. On standing, liver volume was unrelated to BP drop but was associated with successful BP return-to-baseline. Red cell and plasma volume were associated positively with liver volume. Multivariate analysis confirmed return-to-baseline BP on standing which was independently associated with liver volume.""Conclusion: Liver volumes were smaller in CFS compared to controls. The relationship between return-to-baseline BP after standing and liver volume suggests, as in animals, that the liver is involved in maintenance of BP."


 * The prevalence of fatigue, sleepiness, and sleep disorders among petrochemical employees in Iran"Abstract - Background: Fatigue, sleepiness, and sleep disorders adversely impact workers’ health, safety, and performance.""Results: The present study aimed to assess the relationship between fatigue and sleep problems in petrochemical workers in Iran.""Methods: In this cross-sectional study, 501 randomly selected employees of the petrochemical industry participated. The Persian version of Swedish Occupational Fatigue Inventory (P-SOFI-20) and the Persian version of Occupational Fatigue/Exhaustion Recovery (P-OFFER-15) were used to assess fatigue dimensions. Severity of sleepiness was measured by the Karolinska Sleepiness Scale (KSS).""Results: The petrochemical employees reported moderate levels of fatigue. The results also revealed that mean scores on different fatigue dimensions were significantly higher among those who had sleep disorders as compared to individuals without sleep disorders (P < 0.001). The KSS data showed that these employees also suffered from sleepiness. Significant positive relationships were found between sleepiness and fatigue (P-SOFI-20).""Conclusion: Petrochemical employees suffered from fatigue and sleepiness concurrently. As such, employees’ health, safety and productivity may be adversely affected."


 * Latent class analysis of a heterogeneous international sample of patients with myalgic encephalomyelitis/chronic fatigue syndrome"Abstract - Background: Individuals with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) routinely display differences in symptomatology, as well as illness course, onset, duration, and functional disability. Given such diversity, previous work has attempted to identify symptom-based ME/CFS subtypes. However, results have been inconsistent.""Purpose: This study sought to elucidate potential subtypes of ME/CFS as well as explore the impact of subtype membership on health functioning.""Methods: Twelve non-core (i.e. less frequently endorsed) symptoms were included in a latent class analysis of 1,210 adults with ME/CFS. Demographic and illness-related predictors of class membership were evaluated with a multinomial logistic regression. ANOVAs were then performed to determine if there were significant differences across class on the eight subscales of the Short-Form Health Survey (SF-36).""Results: A six-class solution was selected, which consisted of one class that was likely to endorse all non-core symptoms, one class that was unlikely to endorse any non-core symptoms, and four classes that were likely to endorse either one or two non-core symptom domains (i.e. circulatory/neuroendocrine impairment, orthostatic intolerance, and gastro-intestinal distress). Significant functioning differences by class were present for all SF-36 subscales.""Conclusions: These results are suggestive of subtypes of ME/CFS and, if replicated, may assist physicians in providing tailored treatment to patients and allow researchers to form more homogeneous samples."