Evidence browser

E2 ModerateCohortPEM not requiredCase-Control

Vitamin B status in patients with chronic fatigue syndrome.

Heap, L C, Peters, T J, Wessely, S·Journal of the Royal Society of Medicine·1999

This study tested whether people with ME/CFS have lower levels of three B vitamins (B6, B2, and B1) compared to healthy people. Researchers measured how well these vitamins work in red blood cells from 12 ME/CFS patients and 18 healthy controls. They found that all three B vitamins appeared to be functioning less effectively in ME/CFS patients, suggesting a possible vitamin deficiency that might contribute to symptoms.

Energy Metabolism

Mercury and nickel allergy: risk factors in fatigue and autoimmunity.

Sterzl, Ivan, Procházková, Jarmila, Hrdá, Pavlína et al.·Neuro endocrinology letters·1999

This study tested whether allergies to metals like mercury (found in old dental fillings) and nickel might trigger fatigue and autoimmune problems in people with ME/CFS. Researchers compared three groups of tired patients with healthy controls and found that people with fatigue were more sensitive to these metals. When some patients had their mercury-containing fillings removed and replaced, their fatigue improved significantly.

Acute fatigue in chronic fatigue syndrome patients.

Smith, A P, Borysiewicz, L, Pollock, J et al.·Psychological medicine·1999

This study tested whether people with ME/CFS get tired more quickly during mental tasks than healthy people. Researchers compared 67 ME/CFS patients with 126 healthy controls while they performed attention tests over a long session. ME/CFS patients performed worse than healthy people, and the gap widened as fatigue set in, suggesting they struggle more with mental tiredness.

Cognitive Impairment

Chronic fatigue syndrome: gender differences in the search for legitimacy.

Clarke, J N·The Australian and New Zealand journal of mental health nursing·1999

This study interviewed 59 people with ME/CFS (18 men and 41 women) about their experiences with the illness and how doctors treated them. While men and women described similar symptoms and the disease itself affected them in comparable ways, they experienced very different treatment from healthcare providers. The study suggests that gender plays an important role in how seriously doctors take ME/CFS patients and how they are believed.

E2 ModerateBehavioralPEM not requiredCross-Sectional

[Patients with fatigue in family practice: prevalence and treatment].

Kenter, E G, Okkes, I M·Nederlands tijdschrift voor geneeskunde·1999

This study looked at how often people visit their doctor complaining of fatigue and what doctors do about it. Researchers tracked visits from general practitioners across the Netherlands over 10 years, involving over 93,000 patient visits. They found that about 92 out of every 1,000 patients saw their doctor each year because of fatigue, but only about 4% had fatigue lasting 6 months or longer.

Diagnostics

Assessing illness representations of chronic illness: explorations of their disease-specific nature.

Heijmans, M, de Ridder, D·Journal of behavioral medicine·1998

This study looked at how people with ME/CFS and Addison's disease understand and think about their illnesses. Researchers found that ME/CFS patients and Addison's disease patients organize their illness experiences differently—what matters most to one group may not matter as much to the other. For ME/CFS patients, the key factors were how manageable the disease feels, how serious it is, whether they feel personally responsible, and whether they see external causes as responsible.

E2 ModerateCohortPEM unclearCross-Sectional

Medical evaluation of Persian Gulf veterans with fatigue and/or chemical sensitivity.

Pollet, C, Natelson, B H, Lange, G et al.·Journal of medicine·1998

This study looked at 72 Gulf War veterans who reported severe fatigue and/or chemical sensitivity to see if they had ME/CFS or multiple chemical sensitivity. The researchers found that 33 veterans met the criteria for ME/CFS, and compared them to 95 non-veterans who also had ME/CFS. Interestingly, the veterans' ME/CFS appeared to be milder than the civilians' version, based on symptom severity, activity levels, and ability to work.

E2 ModerateCohortPEM not requiredCase-Control

Reproductive correlates of chronic fatigue syndrome.

Harlow, B L, Signorello, L B, Hall, J E et al.·The American journal of medicine·1998

This study compared reproductive and menstrual histories in women with ME/CFS to healthy women without the condition. Women with ME/CFS reported more gynecologic problems and irregular menstrual cycles, and researchers found signs suggesting ovarian dysfunction—such as polycystic ovary syndrome (PCOS)—occurred more often in the ME/CFS group. The authors propose that hormonal imbalances affecting egg release may contribute to ME/CFS by reducing protective immune effects from certain hormones.

The low dose ACTH test in chronic fatigue syndrome and in health.

Scott, L V, Medbak, S, Dinan, T G·Clinical endocrinology·1998

This study tested whether people with ME/CFS have a subtle problem with their stress hormone system, specifically the pituitary gland's ability to signal the adrenal glands to release cortisol. Using a sensitive test with a very small dose of ACTH (a hormone that triggers cortisol release), researchers found that people with ME/CFS showed a weaker cortisol response than healthy people, suggesting their adrenal system may not be functioning optimally.

Salivary cortisol profiles in chronic fatigue syndrome.

Wood, B, Wessely, S, Papadopoulos, A et al.·Neuropsychobiology·1998

This study measured cortisol (a stress hormone) levels in the saliva of 10 people with ME/CFS and 10 healthy people over a 16-hour period. Contrary to some earlier research, people with ME/CFS actually had slightly higher cortisol levels on average than healthy controls. This finding suggests that low cortisol is not the cause of fatigue in ME/CFS.

Evaluating neuropsychological impairment in chronic fatigue syndrome.

Vercoulen, J H, Bazelmans, E, Swanink, C M et al.·Journal of clinical and experimental neuropsychology·1998

This study looked at whether people with ME/CFS have problems with thinking, memory, and concentration. Researchers tested patients using standard cognitive tests and also asked them to report their own memory and concentration difficulties. Surprisingly, most patients performed normally on the tests, and there was no clear connection between test results and what patients reported experiencing in daily life.

Cognitive Impairment

BiomarkersEnergy Metabolism

Low levels of serum acylcarnitine in chronic fatigue syndrome and chronic hepatitis type C, but not seen in other diseases.

Kuratsune, H, Yamaguti, K, Lindh, G et al.·International journal of molecular medicine·1998

Researchers measured a substance called acylcarnitine in the blood of people with ME/CFS and compared it to healthy people and those with other diseases. They found that people with ME/CFS had significantly lower levels of this substance, and this same pattern appeared in both Japanese and Swedish patients. Importantly, this low level was only seen in ME/CFS and one other condition (chronic hepatitis C), not in other common diseases like diabetes or high blood pressure.

E2 ModerateCohortPEM not requiredObservational

A study of the immunology of the chronic fatigue syndrome: correlation of immunologic parameters to health dysfunction.

Hassan, I S, Bannister, B A, Akbar, A et al.·Clinical immunology and immunopathology·1998

This study examined immune system markers in 44 people with ME/CFS to see how these markers related to symptom severity and mental health. Researchers found that ME/CFS patients had unusual patterns in their immune cells—specifically, signs of increased immune activation and changes in how lymphocytes (white blood cells) behave. These immune changes correlated with worse physical function, pain, and mental health symptoms.

E2 ModerateCohortPEM unclearCross-Sectional

Secretion of growth hormone in patients with chronic fatigue syndrome.

Berwaerts, J, Moorkens, G, Abs, R·Growth hormone & IGF research : official journal of the Growth Hormone Research Society and the International IGF Research Society·1998

This study looked at growth hormone levels in people with ME/CFS, because low growth hormone has been seen in related conditions like fibromyalgia. Researchers tested 20 ME/CFS patients and compared them to healthy controls, measuring growth hormone in different ways. They found that ME/CFS patients had lower levels of a growth hormone marker (IGF-I) and tended to produce less growth hormone at night, though other growth hormone tests were similar between groups.

Relation between neuropsychological impairment and functional disability in patients with chronic fatigue syndrome.

Christodoulou, C, DeLuca, J, Lange, G et al.·Journal of neurology, neurosurgery, and psychiatry·1998

This study looked at whether memory and attention problems in ME/CFS patients are linked to how much their daily activities are limited. Researchers tested 53 ME/CFS patients and 32 healthy people on memory and concentration, and found that patients with more failing test scores reported spending significantly more days inactive. Importantly, this connection held true even when accounting for depression, suggesting the cognitive problems themselves—not just mood—contribute to disability.

Cognitive Impairment

E2 ModerateBehavioralPEM not requiredCross-Sectional

Prevalence of chronic fatigue syndrome in a community population in Japan.

Kawakami, N, Iwata, N, Fujihara, S et al.·The Tohoku journal of experimental medicine·1998

This Japanese study looked at how common ME/CFS is in everyday communities by interviewing 137 people. Researchers found that about 1 in 67 people had severe, persistent fatigue that met ME/CFS criteria and significantly disrupted their daily life. The findings suggested ME/CFS might be more common in Japan than in Western countries studied previously.

Diagnostics

Chronic fatigue syndrome and seasonal affective disorder: comorbidity, diagnostic overlap, and implications for treatment.

Terman, M, Levine, S M, Terman, J S et al.·The American journal of medicine·1998

This study looked at whether ME/CFS symptoms get worse during winter months, similar to seasonal depression. Researchers asked 110 ME/CFS patients about their symptoms in summer and winter, and found that about one-third showed a seasonal pattern with winter worsening. This suggests that some ME/CFS patients might benefit from light therapy, a treatment commonly used for seasonal depression.

Sleep

E2 ModerateBehavioralPEM not requiredCase-Control

Chronic fatigue syndrome: identification of distinct subgroups on the basis of allergy and psychologic variables.

Borish, L, Schmaling, K, DiClementi, J D et al.·The Journal of allergy and clinical immunology·1998

This study looked at whether allergies and psychological factors play a role in ME/CFS. Researchers compared 18 people with ME/CFS to healthy controls, people with allergies, and people with depression. They found that people with ME/CFS had different immune molecules (called cytokines) in their blood compared to healthy people, similar to those with allergies. Interestingly, people with ME/CFS who also had certain psychological profiles showed different immune patterns, suggesting that both allergies and how the mind responds to them may contribute to ME/CFS in some patients.

E2 ModerateCohortPEM not requiredCase-Control

Naloxone-mediated activation of the hypothalamic-pituitary-adrenal axis in chronic fatigue syndrome.

Scott, L V, Burnett, F, Medbak, S et al.·Psychological medicine·1998

This study looked at whether an opioid-blocking drug called naloxone could trigger the body's stress hormone system in ME/CFS patients versus healthy people. The researchers found that when given naloxone, ME/CFS patients had a blunted response in one stress hormone (ACTH) compared to healthy controls, suggesting that excess opioids are not the primary cause of the stress hormone problems seen in ME/CFS.