TGI Friday! Our weekly round-up of recently published research abstracts | 20 May 2016

From Health Psychology, published online on 16 May, 2016. (Full text available).

Emotional Suppression in Chronic Fatigue Syndrome: Experimental Study.

Katharine A. Rimes, PhD, Joanna Ashcroft, PsyD, Lauren Bryan, MSc, and Trudie Chalder, PhD.
King's College, London.

Abstract

OBJECTIVE

Emotional processing differences in chronic fatigue syndrome (CFS) have been reported but have rarely been investigated experimentally. This study used self-report, observer ratings, and electrodermal responses to test hypotheses about emotion suppression and autonomic reactivity.

METHODS

Eighty adults with CFS and 80 healthy controls (HC) watched a distressing film clip. Half of each group were instructed to suppress their emotions and half were told to express their feelings as they wished.

Their reactions were filmed and rated by independent observers. Electrodermal activity (skin conductance response) was used as a measure of sympathetic nervous system arousal.

RESULTS

CFS participants reported higher anxiety and sadness than the HC, both before and after the film. However, observers rated the CFS group as having lower emotional expression than HC in both emotional suppression and expression choice conditions. Beliefs about the unacceptability of negative emotions were associated with greater self-reported suppression. Electrodermal responses were greater in the CFS group than HC participants. Higher skin conductance responses were associated with larger posttask increases in fatigue in the CFS participants but not in the HC.

CONCLUSIONS

CFS participants had lower observer-rated emotional expression than HC, despite greater distress and higher autonomic arousal. This may have implications for their ability to access social support at times of stress. As the degree of autonomic arousal was associated with short-term increases in fatigue in the CFS participants, this requires further investigation as a contributory factor for this condition.

From Acta Clinica Belgica: International Journal of Clinical and Laboratory Medicine. published online on 3 May 2016.

Factors determining fatigue in the chronic fatigue syndrome: a path analysis

Els Tobback(a,b*), Ignace Hanoulle(a), An Mariman(a,b), Liesbeth Delesie(a,b), Dirk Pevernagie(c,d) Dirk Vogelaers(a,b,d)
a) Department of General Internal Medicine, University Hospital Ghent, Ghent, Belgium
b) Department of General Internal Medicine, Centre for Neurophysiologic Monitoring, University Hospital Ghent, Ghent, Belgium
c) Sleep Medicine Centre, Kempenhaeghe Foundation, Heeze, The Netherlands
d) Faculty of Medicine and Health Sciences, Department of Internal Medicine, University of Ghent, Ghent, Belgium

Abstract

OBJECTIVES

To explore the interrelationship of different dimensions (fatigue, neuroticism, sleep quality, global mental and physical health) in patients with chronic fatigue syndrome (CFS).

METHODS

Patients meeting the Fukuda criteria of CFS filled out two independent fatigue scales (Fatigue Questionnaire, FQ and Checklist Individual Strength, CIS), NEO-Five Factor Inventory (NEO-FFI), Pittsburgh Sleep Quality Index (PSQI) and Medical Outcomes Study 36-item Short Form Health Survey (SF36). Exploratory and confirmatory path analyses were performed.

RESULTS

Out of 226 eligible patients, 167 subjects were included (mean age 39.13 years, SD 10.14, 92% female). In a first exploratory path analysis, using FQ for assessment of fatigue, night-time PSQI sleep quality had a direct effect on SF36 physical quality of life (PQoL) and no effect on FQ fatigue. This was confirmed by a subsequent path analysis with CIS fatigue and by confirmatory path analyses in 81 patients. These unexpected results raised the question whether FQ or CIS fatigue sufficiently operationalizes fatigue in CFS patients.

CONCLUSIONS

Poor sleep quality seems to directly impact on mental quality of life (MQoL) and PQoL without mediation of fatigue assessed with FQ and CIS. A more cohesive framework needs to be developed with more comprehensive clinical tools for the different dimensions in the construct of CFS.

From Clinical Epidemiology, 17 May 2016.

Epidemiological characteristics of chronic fatigue syndrome/myalgic encephalomyelitis in Australian patients

Samantha C Johnston(1,2), Donald R Staines(1). Sonya M Marshall-Gradisnik(1,2).
1)National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland
2)School of Medical Sciences, Griffith University, Parklands, QLD, Australia

Abstract

BACKGROUND

No epidemiological investigations have previously been conducted in Australia according to the current clinical definitions of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). The aim of this study was to describe sociodemographic and illness characteristics of Australian patients with CFS/ME.

METHODS

A cross-sectional survey on the medical history of patients enrolled in an Australian CFS/ME research database between April 2013 and April 2015. Participants were classified according to Fukuda criteria and International Consensus Criteria.

RESULTS

A total of 535 patients diagnosed with CFS/ME by a primary care physician were identified.

The mean age of all patients was 46.4 years (standard deviation 12.0); the majority were female (78.61%), Caucasian, and highly educated. Of these, 30.28% met Fukuda criteria. A further 31.96% met both Fukuda criteria and International Consensus Criteria.

There were 14.58% reporting chronic fatigue but did not meet criteria for CFS/ME and 23.18% were considered noncases due to exclusionary conditions. Within those meeting CFS/ME criteria, the most common events prior to illness included cold or flu, gastrointestinal illness, and periods of undue stress.

Of the 60 symptoms surveyed, fatigue, cognitive, and short-term memory symptoms, headaches, muscle and joint pain, unrefreshed sleep, sensory disturbances, muscle weakness, and intolerance to extremes of temperature were the most commonly occurring symptoms (reported by more than two-thirds of patients).

Significant differences in symptom occurrence between Fukuda- and International Consensus Criteria-defined cases were also identified.

CONCLUSION

This is the first study to summarize sociodemographic and illness characteristics of a cohort of Australian CFS/ME patients. This is vital for identifying potential risk factors and predictors associated with CFS/ME and for guiding decisions regarding health care provision, diagnosis, and management.

From the Journal of Translational Medicine, 5 May 2016 (open access).

Altered neuroendocrine control and association to clinical symptoms in adolescent chronic fatigue syndrome: a cross-sectional study

Vegard Bruun Wyller(1,2), Valieria Vitelli(3), Dag Sulheim (4,5), Even Fagermoen (6,7), Anette Winger (8), Kristin Godang (9) and Jens Bollerslev (9).
1) Division of Medicine and Laboratory Sciences, Medical Faculty, University of Oslo
2) Department of Paediatrics, Akershus University Hospital
3) Department of Biostatistics, Institute of Basic Medical Sciences, Oslo Centre for Biostatistics and Epidemiology, University of Oslo
4) Department of Paediatrics, Oslo University Hospital
5) Department of Paediatrics, Lillehammer County Hospital
6) Institute of Clinical Medicine, Medical Faculty, University of Oslo
7) Department of Anesthesiology and Critical Care, Oslo University Hospital
8) Institute of Nursing Sciences, Oslo and Akershus University College of Applied Sciences
9) Section of Specialized Endocrinology, Department of Endocrinology, Oslo University Hospital Rikshospitalet

Abstract

BACKGROUND

Chronic fatigue syndrome (CFS) is a common and disabling disorder, and a major threat against adolescent health. The pathophysiology is unknown, but alteration of neuroendocrine control systems might be a central element, resulting in attenuation of the hypothalamus–pituitary–adrenalin (HPA) axis and enhancement of the sympathetic/adrenal medulla (SAM) system. This study explored differences in neuroendocrine control mechanisms between adolescent CFS patients and healthy controls, and whether characteristics of the control mechanisms are associated with important clinical variables within the CFS group.

METHODS

CFS patients 12–18 years of age were recruited nation-wide to a single referral center as part of the NorCAPITAL project. A broad case definition of CFS was applied. A comparable group of healthy controls were recruited from local schools. A total of nine hormones were assayed and subjected to network analyses using the ARACNE algorithm. Symptoms were charted by a questionnaire, and daily physical activity was recorded by an accelerometer.

RESULTS

A total of 120 CFS patients and 68 healthy controls were included. CFS patients had significantly higher levels of plasma norepinephrine, plasma epinephrine and plasma FT4, and significantly lower levels of urine cortisol/creatinine ratio. Subgrouping according to other case definitions as well as adjusting for confounding factors did not alter the results. Multivariate linear regression models as well as network analyses revealed different interrelations between hormones of the HPA axis, the SAM system, and the thyroid system in CFS patients and healthy controls. Also, single hormone degree centrality was associated with clinical markers within the CFS group.

CONCLUSION

This study reveals different interrelation between hormones of the HPA axis, the SAM system, and the thyroid system in CFS patients and healthy controls, and an association between hormone control characteristics and important clinical variables in the CFS group. These results add to the growing insight of CFS disease mechanisms.

Trial registration Clinical Trials NCT01040429

From Acta Paediatrica, published online 13 May 2016.

Cow's Milk Protein Intolerance in Adolescents and Young Adults with Chronic Fatigue Syndrome

Peter C. Rowe(1,*), Colleen L. Marden(1), Samantha E. Jasion(1), Erica M. Cranston(1,2), Marissa A. K. Flaherty(1,2) and Kevin J. Kelly(3)
1) Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
2) University of Maryland School of Medicine, Baltimore, MD
3) Pediatric Specialty Care, Willow Grove, PA
*Corresponding author: Peter C. Rowe, MD; Division of General Pediatrics and Adolescent Medicine; 200 N. Wolfe St., Room 2077, Baltimore, MD 21287; Tel: 410-955-9229; Fax: 410-614-1178; prowe@jhmi.edu

Abstract

AIM

To examine the prevalence, clinical features, and influence on illness severity of cow's milk protein intolerance in young people with chronic fatigue syndrome.

METHODS

In a 2 year prospective study of 55 adolescents and young adults with chronic fatigue syndrome, we defined intolerance to milk protein if subjects reported (1) no evidence of immediate or anaphylactic reactions to milk, (2) at least 2 of the following 3 chronic symptoms: gastroesophageal reflux, early satiety, and epigastric/abdominal pain, (3) improvement in upper gastrointestinal symptoms on a milk protein elimination diet, and (4) at least 2 recurrences of upper gastrointestinal symptoms > 2 hours following open re-exposure to milk protein. Subjects completed three quality of life surveys at baseline and at 6 months.

RESULTS

The mean (SD) age of the 55 participants was 16.5 (2.1) years. Seventeen (31%; 95% CI, 19-43%) met study criteria for cow's milk protein intolerance. Compared to milk-tolerant subjects, milk-sensitive participants had significantly worse health-related quality of life at baseline but not at 6 months (after institution of the milk-free diet).

CONCLUSION

Cow's milk protein intolerance is a common problem in young people with chronic fatigue syndrome, and is a treatable contributor to their symptoms.