Evidence browser

Normal red cell magnesium concentrations and magnesium loading tests in patients with chronic fatigue syndrome.

Hinds, G, Bell, N P, McMaster, D et al.·Annals of clinical biochemistry·1994

This study tested whether people with ME/CFS have low magnesium levels, since some people believed magnesium supplements might help with fatigue. Researchers measured magnesium in red blood cells from 89 ME/CFS patients and compared them to healthy people, then did additional tests on six patients. They found no difference in magnesium levels between the two groups.

Cognitive functioning and depression in patients with chronic fatigue syndrome and multiple sclerosis.

Krupp, L B, Sliwinski, M, Masur, D M et al.·Archives of neurology·1994

This study compared thinking and memory problems in people with ME/CFS, multiple sclerosis (MS), and healthy controls. People with ME/CFS showed some cognitive difficulties, particularly in processing speed and memory tasks, and had higher rates of depression. However, their cognitive problems were less widespread than those seen in MS patients, and some thinking difficulties in ME/CFS appeared linked to depression rather than the illness itself.

E2 ModerateCohortPEM not requiredObservational

Low grade pyrexia: is it chronic fatigue syndrome?

Anand, A C, Kumar, R, Rao, M K et al.·The Journal of the Association of Physicians of India·1994

This study followed 87 patients who had a persistent low-grade fever (99-101°F) along with fatigue, muscle pain, and joint pain. Doctors ran many tests looking for infections, autoimmune diseases, or cancer, but found nothing abnormal. Most patients gradually improved over time, with about half becoming symptom-free within three years. The researchers suggest this condition might be related to ME/CFS.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Simultaneous measurement of antibodies to Epstein-Barr virus, human herpesvirus 6, herpes simplex virus types 1 and 2, and 14 enteroviruses in chronic fatigue syndrome: is there evidence of activation of a nonspecific polyclonal immune response?

Manian, F A·Clinical infectious diseases : an official publication of the Infectious Diseases Society of America·1994

This study looked at whether people with ME/CFS have higher levels of antibodies (immune proteins that fight viruses) to multiple different viruses compared to healthy people. Researchers tested blood samples from 20 ME/CFS patients and 20 healthy controls for antibodies to five different viruses. They found that most ME/CFS patients had elevated antibodies to at least one virus, but the pattern didn't suggest a generalized immune overreaction affecting all viruses equally.

Immune System

A comparison of neuropsychiatric characteristics in chronic fatigue syndrome, multiple sclerosis, and major depression.

Pepper, C M, Krupp, L B, Friedberg, F et al.·The Journal of neuropsychiatry and clinical neurosciences·1993

This study compared the emotional and psychological characteristics of people with ME/CFS to those with multiple sclerosis and major depression. The researchers found that people with ME/CFS experienced depression, but overall had fewer psychiatric and personality-related issues compared to those with major depression alone. Interestingly, ME/CFS patients were more likely to develop depression after their illness began, compared to MS patients.

Behavioural problems associated with the chronic fatigue syndrome.

Smith, A P, Behan, P O, Bell, W et al.·British journal of psychology (London, England : 1953)·1993

This study tested whether people with ME/CFS actually experience the memory, concentration, and coordination problems they report. Researchers gave 57 ME/CFS patients and 19 healthy controls a series of computerized tests measuring thinking speed, memory, attention, and motor skills. ME/CFS patients performed worse on many tests—they were slower at tasks requiring coordination, had trouble focusing, and struggled with complex reasoning—even though their depression and anxiety levels didn't fully explain these differences.

E2 ModerateCohortPEM unclearCase-Control

Persistence of enterovirus RNA in muscle biopsy samples suggests that some cases of chronic fatigue syndrome result from a previous, inflammatory viral myopathy.

Bowles, N E, Bayston, T A, Zhang, H Y et al.·Journal of medicine·1993

Researchers tested muscle samples from people with post-viral fatigue syndrome (a condition similar to ME/CFS that develops after a viral infection) and found evidence of enterovirus RNA in about 26% of samples. This was much higher than in healthy control samples. The study suggests that some cases of ME/CFS may develop after a viral infection causes inflammation in the muscles, similar to how viral heart infections can lead to long-term heart problems.

E2 ModerateCohortPEM unclearCase-Control

Information processing efficiency in chronic fatigue syndrome and multiple sclerosis.

DeLuca, J, Johnson, S K, Natelson, B H·Archives of neurology·1993

This study compared thinking and concentration abilities in people with ME/CFS, people with multiple sclerosis (MS), and healthy volunteers. All participants were matched by age and education level. People with ME/CFS and MS both showed difficulty with tasks requiring fast, complex thinking compared to healthy controls, suggesting that ME/CFS may affect how the brain processes information.

Prevalence of chronic fatigue syndrome-related symptoms among nurses.

Jason, L A, Taylor, S L, Johnson, S et al.·Evaluation & the health professions·1993

This study looked at how common ME/CFS-related symptoms are among nurses. Researchers surveyed a group of nurses and found that when using different definitions of the illness, more nurses showed signs of ME/CFS than had been found in previous studies of the general population. This was the first study to specifically examine ME/CFS in healthcare workers.

E2 ModerateCohortPEM unclearLongitudinal

Investigation of retroviral involvement in chronic fatigue syndrome.

Folks, T M, Heneine, W, Khan, A et al.·Ciba Foundation symposium·1993

Researchers tested whether certain viruses called retroviruses might be a biological marker that could help diagnose ME/CFS. They looked for five different retroviruses in people with ME/CFS and compared them to healthy controls. None of these viruses were found in either group, meaning they cannot be used to identify who has ME/CFS.

Biomarkers

A four-year follow-up study in fibromyalgia. Relationship to chronic fatigue syndrome.

Nørregaard, J, Bülow, P M, Prescott, E et al.·Scandinavian journal of rheumatology·1993

This study followed 91 fibromyalgia patients for about 4 years to see if their muscle pain was caused by other medical conditions and how their symptoms changed over time. Most patients reported their pain got worse, and while many experienced severe fatigue, very few actually met the diagnostic criteria for chronic fatigue syndrome. The good news was that muscle strength remained stable and most cases of fibromyalgia were not caused by an underlying disease.

E2 ModerateCohortPEM unclearLongitudinal

Serum folate and chronic fatigue syndrome.

Jacobson, W, Saich, T, Borysiewicz, L K et al.·Neurology·1993

Researchers measured folic acid levels in the blood of 60 ME/CFS patients and found that about half had lower-than-normal amounts. This suggests that some people with ME/CFS may not have enough folic acid in their body, which is a B vitamin important for many body functions.

[Chronic fatigue syndrome].

Fucíková, T, Petanová, J·Vnitrni lekarstvi·1993

Researchers followed 52 ME/CFS patients for 1 to 14 years to see how they progressed over time. About 20% recovered completely, about 32% improved significantly, and about 15% developed thyroiditis (thyroid inflammation). The treatments used were mainly immune-modulating drugs chosen based on each patient's individual immune test results, though the benefits were only partial.

Immune System

E2 ModerateCohortPEM not requiredObservational

Assessment of a retrovirus sequence and other possible risk factors for the chronic fatigue syndrome in adults.

Khan, A S, Heneine, W M, Chapman, L E et al.·Annals of internal medicine·1993

Researchers tested whether a virus called HTLV-II might be a cause of ME/CFS by comparing blood samples from 21 people with CFS to 21 healthy controls. They found no trace of the HTLV-II virus in any of the participants, and found no differences between the two groups in exposure to activities that spread viruses. This study argues against the idea that HTLV-II is linked to ME/CFS.

Isolated diastolic dysfunction of the myocardium and its response to CoQ10 treatment.

Langsjoen, P H, Langsjoen, P H, Folkers, K·The Clinical investigator·1993

This study looked at heart function in patients with chronic fatigue syndrome (ME/CFS) and compared them to patients with other heart conditions. Researchers found that many of these patients had a specific type of heart problem called diastolic dysfunction—where the heart doesn't relax properly between beats. When patients were given a supplement called CoQ10, their heart function improved and their symptoms got better.

A brief mental fatigue questionnaire.

Bentall, R P, Wood, G C, Marrinan, T et al.·The British journal of clinical psychology·1993

Researchers created a short questionnaire to measure mental tiredness and tested it in people with ME/CFS, depression, recovered ME/CFS, muscle disease, and healthy people. The questionnaire worked well at identifying mental fatigue, but it could not tell the difference between people with ME/CFS and people with depression—both groups reported similar types and amounts of mental tiredness.

E2 ModerateCohortPEM unclearCross-Sectional

The overdiagnosis of Lyme disease.

Steere, A C, Taylor, E, McHugh, G L et al.·JAMA·1993

This study looked at 788 people referred to a Lyme disease clinic who were thought to have Lyme disease. Researchers found that only 23% actually had active Lyme disease, while 57% did not have Lyme disease at all—many of these patients had chronic fatigue syndrome or fibromyalgia instead. The main problem was that patients were being incorrectly diagnosed with Lyme disease and given antibiotics that didn't help because they didn't actually have the infection.

E2 ModerateCohortPEM not requiredObservational

Epidemiology of chronic fatigue syndrome: the Centers for Disease Control Study.

Gunn, W J, Connell, D B, Randall, B·Ciba Foundation symposium·1993

Between 1989 and 1991, the CDC tracked patients with chronic fatigue syndrome across four U.S. cities to understand how common the illness is and who gets it. Researchers found that only about 1 in 4 patients referred to them actually met the strict diagnostic criteria for CFS, while others had different medical conditions or psychiatric histories that might explain their fatigue. The study estimated that CFS affects roughly 2–11 people per 100,000 in the general population, and it most commonly affected women in their 30s.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Chronic fatigue and chronic fatigue syndrome: clinical epidemiology and aetiological classification.

Manu, P, Lane, T J, Matthews, D A·Ciba Foundation symposium·1993

This study looked at 405 patients who came to a hospital complaining of chronic fatigue and tried to figure out what was causing it. Doctors found that most patients had psychiatric conditions like depression or anxiety rather than physical diseases. About 30% of patients met the definition for ME/CFS, and these patients were more likely to attribute their illness to a viral infection than other fatigued patients.