Tag: risk factors

Epidemiologic advances in chronic fatigue syndrome

Abstract:

Epidemiologic studies of chronic fatigue syndrome (CFS) have been hampered by the absence of a specific diagnostic test, but with increasing interest in this disorder there has been a greater understanding of the risk factors, illness patterns, and other aspects of this multisystem disorder.

Working case definitions have been developed for research purposes but they have continued to change over time and have not always been utilized precisely by various investigators. This has been a major factor in the widely varying estimates of prevalence rates, but two different studies using the same working definition and including a medical work-up have estimated the prevalence to be approximately 200/100,000. Clusters of CFS cases, which appear to be related to earlier reports of “epidemic neuromyasthenia”, have attracted considerable attention and appear to be well documented, although investigated with varying methodology and often with dissimilar case definitions.

Risk factors for cases occurring in clusters and sporadically appear to be similar, the most consistent ones being female gender and the co-existence of some form of stress, either physical or psychological. The prognosis of CFS is difficult to predict, although cases occurring as part of clusters appear to have a better prognosis as a group than sporadic cases, and those with an acute onset have a better prognosis than those with gradual onset.

It is highly unlikely that there is a single agent, infectious or noninfectious, that is responsible for more than a small proportion of CFS cases and, at the present time, the risk factors for developing CFS appear to lie more prominently in the host rather than the environment.

 

Source: Levine PH. Epidemiologic advances in chronic fatigue syndrome. J Psychiatr Res. 1997 Jan-Feb;31(1):7-18. http://www.ncbi.nlm.nih.gov/pubmed/9201643

 

Psychosocial risk factors for chronic fatigue and chronic fatigue syndrome following presumed viral illness: a case-control study

Abstract:

This study investigated psychosocial morbidity, coping styles and health locus of control in 64 cases with and without chronic fatigue identified from a cohort of primary care patients recruited 6 months previously with a presumed, clinically diagnosed viral illness. A significant association between chronic fatigue and psychosocial morbidity, somatic symptoms and escape-avoidance coping styles was shown.

Chronic fatigue cases were significantly more likely to have a past psychiatric history and a current psychiatric diagnosis based on a standardized clinical interview. Twenty-three of the cases fulfilled criteria for chronic fatigue syndrome (CFS). Such cases were significantly more fatigued than those not fulfilling criteria, but had little excess psychiatric disorder.

A principal components analysis provided some evidence for chronic fatigue being separable from general psychosocial morbidity but not from the tendency to have other somatic complaints. Past psychiatric history and psychological distress at the time of the viral illness were risk factors for psychiatric ‘caseness’ 6 months later, while presence of fatigue, psychologising attributional style and sick certification were significant risk factors for CFS. These findings extend a previous questionnaire study of predictors of chronic ‘post-viral’ fatigue.

 

Source: Cope H, Mann A, Pelosi A, David A. Psychosocial risk factors for chronic fatigue and chronic fatigue syndrome following presumed viral illness: a case-control study. Psychol Med. 1996 Nov;26(6):1197-209. http://www.ncbi.nlm.nih.gov/pubmed/8931166

 

Chronic fatigue: risk factors for symptom persistence in a 2 1/2-year follow-up study

Abstract:

BACKGROUND: The prolonged disability of patients suffering from chronic fatigue may be due to sustaining factors that are independent of the cause and subject to intervention. This study reexamined a cohort of patients with chronic fatigue to define medical and psychiatric predictors of persistent symptoms.

METHODS: Seventy-eight patients with chronic fatigue present for 6 months or more (not required to meet the Centers for Disease Control case definition for chronic fatigue syndrome [CFS]) completed a self-report, follow-up questionnaire to measure the overall improvement or worsening of their condition at a mean of 2.5 years after their initial examination. At the time of initial evaluation, patients underwent a structured psychiatric examination, physical examination, laboratory studies, and self-report measures of psychological distress and functional disability. The psychiatric examination queried the patient about 28 somatic symptoms that are separate from those associated with CFS. Discriminant analysis was used to determine which variables present at the initial examination were significant predictors of persistent symptoms and disability at 2.5 years.

RESULTS: The factors most important at the time of initial presentation in predicting persistent illness were: (1) more than eight medically unexplained physical symptoms separate from those associated with CFS case definition; (2) lifetime history of dysthymia; (3) duration of chronic fatigue symptoms greater than 1.5 years; (4) less than 16 years of formal education; and (5) age older than 38 years. None of the results of the initial physical examination, or immunologic, general laboratory, or viral antibody measurements were significant in predicting persistence of symptoms. Recovery rates for those who met the criteria for CFS by either of two case definitions were lower than the rate of noncases, but the differences were not statistically significant. The five aforementioned variables formed a significant discriminative function, correctly classifying 78% of those who recovered and 74% of those with persistent symptoms.

CONCLUSIONS: At initial examination, patients with chronic fatigue, more than eight medically unexplained physical symptoms (excluding symptoms in the case criteria for CFS), a lifetime history of dysthymic disorder, longer than 1.5 years of chronic fatigue, less than 16 years of formal education, and who were older than 38 years were the most likely to have persistence of symptoms of chronic fatigue at the 2.5-year follow-up.

 

Source: Clark MR, Katon W, Russo J, Kith P, Sintay M, Buchwald D. Chronic fatigue: risk factors for symptom persistence in a 2 1/2-year follow-up study. Am J Med. 1995 Feb;98(2):187-95. http://www.ncbi.nlm.nih.gov/pubmed/7847436

 

Predictors of chronic “postviral” fatigue

Abstract:

We set out to determine the relation between a general practitioner (GP) diagnosis of viral illness and development of chronic fatigue 6 months later. 618 subjects who attended GPs clinics in London, south, and southwest England and who received a diagnosis of viral illness were followed prospectively and fatigue was assessed by questionnaire after 6 months. At presentation, GPs recorded fatigue in 62.6% of subjects, usually since the onset of symptoms. 502 (81.2%) subjects completed the 6-month questionnaire, of whom 88 (17.5%) met criteria for chronic fatigue and 65 (12.9%) had no reported fatigue before the viral illness.

Compared with a similar group of non-postviral GP attenders, the risk ratio for chronic fatigue in the present cohort was 1.45 (95% CI 1.14-2.04). Infective symptoms did not predict fatigue 6 months later. Psychiatric morbidity, belief in vulnerability to viruses, and attributional style at initial presentation were all associated with self-designated postviral fatigue.

Logistic regression showed that somatic attributional style, less definite diagnosis by the GP, and sick certification were the only significant predictors of chronic fatigue after viral infection when other factors were controlled for. Chronic severe fatigue 6 months after GP-diagnosed viral illness is related to symptom-attributional style and doctor behaviour, rather than to features of the viral illness. Some subjects with apparent postviral fatigue had complained of tiredness before their presentation with a viral illness.

Comment in:

Chronic fatigue syndrome. [Lancet. 1994]

Chronic fatigue syndrome. [Lancet. 1994]

 

Source: Cope H, David A, Pelosi A, Mann A. Predictors of chronic “postviral” fatigue. Lancet. 1994 Sep 24;344(8926):864-8. http://www.ncbi.nlm.nih.gov/pubmed/7916407

 

Concurrent sick building syndrome and chronic fatigue syndrome: epidemic neuromyasthenia revisited

Abstract:

Sick building syndrome (SBS) is usually characterized by upper respiratory complaints, headache, and mild fatigue. Chronic fatigue syndrome (CFS) is an illness with defined criteria including extreme fatigue, sore throat, headache, and neurological symptoms.

We investigated three apparent outbreaks of SBS and observed another more serious illness (or illnesses), characterized predominantly by severe fatigue, that was noted by 9 (90%) of the 10 teachers who frequently used a single conference room at a high school in Truckee, California; 5 (23%) of the 22 responding teachers in the J wing of a high school in Elk Grove, California; and 9 (10%) of the 93 responding workers from an office building in Washington, D.C.

In those individuals with severe fatigue, symptoms of mucous membrane irritation that are characteristic of SBS were noted but also noted were neurological complaints not typical of SBS but quite characteristic of CFS. We conclude that CFS is often associated with SBS.

 

Source: Chester AC, Levine PH. Concurrent sick building syndrome and chronic fatigue syndrome: epidemic neuromyasthenia revisited. Clin Infect Dis. 1994 Jan;18 Suppl 1:S43-8. http://www.ncbi.nlm.nih.gov/pubmed/8148452

 

The chronic fatigue syndrome

Abstract:

CFIDS (chronic fatigue and immune disfunction syndrome) is also known as CFS (chronic fatigue syndrome), CEBV (chronic Epstein-Barr virus), M.E. (myalgic encephalomyelitis), yuppie flu and by other names.

It is a complex illness characterized by incapacitating fatigue (experienced as exhaustion and extremely poor stamina), neurological problems and a constellation of symptoms that can resemble many disorders, including; mononucleosis, multiple sclerosis, fibromyalgia, AIDS-related complex (ARC) and autoimmune diseases such as lupus. These symptoms tend to wax and wane, but any often severely debilitating and may last for many months or years. All sections of the population (including children) are at risk, but women under 45 seem to be most susceptible.

The investigators suggest that CFIDS results from dysfunction of the immune system. The exact nature of this dysfunction is not yet well defined, but it can generally be viewed as an unregulated or overactive state which is responsible for most of the symptoms. There is also evidence of some immune suppression in CFIDS. None of the treatments is consistently satisfactory, but some may be helpful: psychotherapy, physiotherapy, exercise programs, acupunctures, small doses of antidepressants, etc.

 

Source: Artsimovich NG, Chugunov VS, Kornev AV, Ivanova TM, Chugunov AV, Oprishchenko MA. The chronic fatigue syndrome. Zh Nevrol Psikhiatr Im S S Korsakova. 1994;94(5):47-50. [Article in Russian] http://www.ncbi.nlm.nih.gov/pubmed/7900453

 

Chronic fatigue syndrome: immune dysfunction, role of pathogens and toxic agents and neurological and cardial changes

Abstract:

375 patients with chronic fatigue syndrome (CFS) were examined using a standardized questionnaire and subsequent interview on 11 risk factors and 45 symptoms. Additionally immunologic, serologic, toxicologic, neuroradiologic, neurophysiologic and cardiologic investigations were performed.

Immunologic tests showed cellular immunodeficiences particularly in functional regard (pathological lymphocyte stimulation in 50% of the patients, disorders of granulocyte function in 44%). Furthermore variable deviations were found in the lymphocyte subpopulations (CD3, CD4, CD8, CD19, DR, Leu 11 + 19).

In the humoral part tendencies to low IgG-3- and IgG-1-subclass-levels occurred (59% respectively 11% of the patients) also as decreases in complement system (CH50, C3, C4, C1-esterase-inhibitor). In the group of activation markers and cytokines 42% of the investigated patients had circulating immune complexes (CIC), 47% increases of tumor-necrosis-factor (TNF-a) and 21% increases of soluble interleukin-2-receptor (IL-2-R).

The increased occurrence of autoantibodies in the CFS-patients (specially antinuclear anti-bodies [ANA], microsomal thyroid antibodies) suggest, that CFS is associated with or the beginning of manifest autoimmune disease.

Under the pathogens 78% of the patients had a striking serological constellation of Epstein-Barr-Virus (EBV-EA positive, low EBNA-titers), in the HHV-6-Virus 47% showed increased antibody-titers. Tests on further herpes viruses and on Borreliae, Chlamydiae, Candida and Amoebae were positive in 8 to 36% of the examined patients. Furthermore there were found variable deficits of vitamins and trace elements also as hormonal disturbances.

In 26% of the patients there were hints of pollutants (e.g. wood preservatives), in 32 patients blood-levels of pentachlorphenol (PCP) and gamma-hexachlorcyclohexan (γ-HCH, lindan) were measured, which showed vanable increases.

178 (83%) of 225 investigated patients showed disturbances of perfusion in cerebral SPECT imaging, 65 (29%) of 218 patients cerebral punctuate signal changes in cranial magnetic resonance imaging (MRI).

Neurophysiologic measurements (motor evoked potentials, MEP) showed in about 50% of 112 patients prolonged central motor conduction times. 62 patients were additionally investigated by myocardial SPECT-imaging, which was abnormal under exercise in 73%. Our data confirm the concept, that CFS must be considered as a complex psycho-neuro-immunological disorder.

 

Source: Hilgers A, Frank J. Chronic fatigue syndrome: immune dysfunction, role of pathogens and toxic agents and neurological and cardial changes. Wien Med Wochenschr. 1994;144(16):399-406.[Article in German] http://www.scopus.com/record/display.uri?eid=2-s2.0-0027940724&origin=inward&txGid=0

and http://www.ncbi.nlm.nih.gov/pubmed/7856214

 

 

Chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) is defined by symptoms and diagnosed without any objective diagnostic tests. Risk factors for developing CFS may include infection, psychiatric disorders, and allergies. Modest dysfunction of multiple organ systems, including the immune, central nervous, endocrine, and muscular systems, have been identified in cases of CFS. Symptoms of various organic, psychiatric, and poorly understood disorders overlap those of CFS. There is no known cure for CFS; however, exercise, counseling, and medications may provide symptomatic relief.

 

Source: Klonoff DC. Chronic fatigue syndrome. Clin Infect Dis. 1992 Nov;15(5):812-23. http://www.ncbi.nlm.nih.gov/pubmed/1445980

 

Alleged link between hepatitis B vaccine and chronic fatigue syndrome

In 1989, 3456 cases of hepatitis B were reported in Canada. It is generally accepted that the true incidence of the disease is about 10 times the reported incidence.

Hepatitis B virus is a major cause of acute and chronic hepatitis, cirrhosis and primary hepatocellular carcinoma. Chronic hepatitis may develop in 10% of infected adults and 90% of infected infants and may progress to cirrhosis and hepatocellular carcinoma. In its acute form hepatitis B is fatal in a small number of cases. The disease is transmitted through sexual contact and infected blood and other body fluids. Carriers frequently show no symptoms until later in life and may therefore infect others unknowingly.

Hepatitis B vaccine has been used in populations that have an established risk of infection with known consequences (e.g., health care workers, male homosexuals and injection drug users).

Recent attention in the Canadian press has focused on the possible association between hepatitis B vaccination and chronic fatigue syndrome (CFS).

You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1488229/pdf/cmaj00290-0039.pdf

 

Source: [No authors listed] Alleged link between hepatitis B vaccine and chronic fatigue syndrome. CMAJ. 1992 Jan 1;146(1):37-8. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1488229/

 

Risk factors associated with chronic fatigue syndrome in a cluster of pediatric cases

Abstract:

After seven pediatric cases of chronic fatigue syndrome (CFS) were diagnosed in a farming community in upstate New York, a questionnaire regarding symptoms and potential risk factors of CFS was distributed to all students enrolled in the same school district.

Twenty-one students with symptoms of CFS were identified. Two controls per case matched for age and sex were randomly selected from questionnaire respondents. Health status was verified for all subjects by telephone, and diagnosis of CFS was confirmed by a physician.

Information was collected on the following factors: symptoms of CFS among other family members; history of allergy/asthma; consumption of raw milk, raw eggs, raw cheese, or raw meat; water supply; exposure to animals; home heating source; proximity to farmland/orchards; tick bite; blood transfusion; camping; and appendicitis.

Logistic-regression analyses indicated that the best model (characterized by symptoms among other family members, recent ingestion of raw milk, and history of allergy/asthma) produced significant estimates of relative risk (P less than .05) of 35.9, 44.3, and 23.3, respectively, for the three factors (corrections were made for the effect of the other covariates).

These data suggest that a combination of host and environmental factors, including an infectious agent or agents, are involved in the etiology of CFS.

 

Source: Bell KM, Cookfair D, Bell DS, Reese P, Cooper L. Risk factors associated with chronic fatigue syndrome in a cluster of pediatric cases. Rev Infect Dis. 1991 Jan-Feb;13 Suppl 1:S32-8. http://www.ncbi.nlm.nih.gov/pubmed/2020801