The epidemiology of chronic fatigue in the Swedish Twin Registry

Abstract:

BACKGROUND: Chronic fatigue syndrome (CFS) remains an idiopathic and controversial entity.

METHOD: We screened 31405 individual members of the Swedish Twin Registry (aged 42-64 years) for the symptoms of fatiguing illness via a telephone questionnaire. We refined self-reported symptoms via data from several national registries and from physician review of all available medical records in order to approximate closely the dominant case definition of CFS.

FINDINGS: The 6-month prevalence of CFS-like illness was 2.36% (95% CI 2.19-2.53) and was markedly higher in women than men, odds ratio 3.92 (95% CI 3.24-4.72) with no significant association with age or years of education. There was a highly significant association with occupation that disappeared after accounting for gender.

INTERPRETATION: CFS-like illness may be more common that previously acknowledged. There is a marked increase in risk by gender. Previous reports that CFS is more prevalent in individuals in certain occupational categories were not confirmed and may have been due to confounding by gender.

 

Source: Evengård B, Jacks A, Pedersen NL, Sullivan PF. The epidemiology of chronic fatigue in the Swedish Twin Registry. Psychol Med. 2005 Sep;35(9):1317-26. http://www.ncbi.nlm.nih.gov/pubmed/16168154

 

Gene expression profiling in the chronic fatigue syndrome

Fatigue is a symptom found in many conditions of disease and illness. Although, unfrequently recognized by the medical profession, it is often of major importance for the patients. Chronic fatigue was reported by 5.9% of the Swedish population in a large telephone-based interview with 31 406 individuals in the Swedish twin registry (STR) [1]. The fatigue had lasted for more than 6 months and caused impairment, e.g. >25% reduction of working capacity. When at least four of eight criteria included in the current definition of chronic fatigue syndrome (CFS) [2] was added 2.4% reported that they suffered from a CFS-like illness.

This costly condition is still an intriguing issue for researchers and clinicians, and ambiguities in the definition have recently been focused upon [3, 4]. An empirical test of the definition was performed with data from the STR where five subgroups were identified: ‘CFS-like’, ‘residual’, ‘rheumatic’, ‘depressive’ and ‘acute physical syndrome’ [5].

We wanted to identify genes in peripheral blood mononuclear cells (PBMCs), which may play an important role in the pathogenesis and diagnostics of CFS, using microarray technology. PBMCs can serve as indicators of illness processes occurring in different parts of the human body. Patients with CFS from a clinic of infectious diseases at a university hospital were stratified according to the STR study findings [5] to sex, illness classification (ICD-10), illness onset type, illness duration and number of symptoms (Table 1).

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Source: Gräns H, Nilsson P, Evengard B. Gene expression profiling in the chronic fatigue syndrome. J Intern Med. 2005 Oct;258(4):388-90. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2796.2005.01548.x/full (Full article)

 

A preliminary epidemiological study and discussion on traditional Chinese medicine pathogenesis of chronic fatigue syndrome in Hong Kong

Abstract:

OBJECTIVE: Our purpose is to conduct an epidemiological study of chronic fatigue syndrome (CFS) and its syndrome types and symptoms of traditional Chinese medicine (TCM) among adults (20-50 years old) in Hong Kong, and to discuss the TCM pathogenesis.

METHODS: DESIGN: Cross-sectional questionnaire survey.

MEASURES: Demographic data, CDC (1994) CFS diagnostic criteria, Trudie Chalder fatigue scale, and China national standard for TCM syndrome types criteria.

SUBJECTS: Twenty to fifty years old adults by convenient sampling.

RESULTS: One thousand and thirteen subjects were successfully interviewed. Five hundred and eighty-five subjects (57.8%) had different levels of fatigue. Sixty-five subjects (6.4%) met CFS diagnostic criteria. In terms of TCM syndrome types, blood stasis due to qi deficiency had the highest prevalence (35.7%) among CFS. In the 54 symptoms investigated in total, the first eight symptoms in order of appearing rates were soreness of loins and weakness in knees, poor spirit, lassitude, pain, insomnia, forgetting, vessels blood stasis, vertigo and dazzle. The mostly appeared tongue figures were pale and corpulent or pale dim tongue proper, white and white greasy tongue coating, and the mostly appeared pulse figure was sunken-thin.

CONCLUSION: The point prevalence of CFS among adults of 20 to 50 years old was found to be 6.4%. The most prevalent TCM syndrome type was blood stasis due to qi deficiency. The TCM pathogenesis of CFS was deficiency of origin, mainly deficiency of qi and kidney, with excess of superficiality.

 

Source: Yiu YM, Qiu MY. A preliminary epidemiological study and discussion on traditional Chinese medicine pathogenesis of chronic fatigue syndrome in Hong Kong. Zhong Xi Yi Jie He Xue Bao. 2005 Sep;3(5):359-62. [Article in Chinese] http://www.ncbi.nlm.nih.gov/pubmed/16159567 View full article in Chinese here: http://www.jcimjournal.com/articles/publishArticles/pdf/200632947810378.pdf

 

Acupuncture and Chinese patent drugs for treatment of chronic fatigue syndrome

We have, in recent years, treated 84 cases of chronic fatigue syndrome with acupuncture therapy and Chinese patent drugs and obtained quite good clinical therapeutic effects. A report follows.

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Source: Lijue Z. Acupuncture and Chinese patent drugs for treatment of chronic fatigue syndrome. J Tradit Chin Med. 2005 Jun;25(2):99-101. http://www.journaltcm.com/modules/Journal/contents/stories/052/6.pdf (Full article)

 

The Chronic Fatigue Syndrome Activities and Participation Questionnaire (CFS-APQ): an overview

Abstract:

Chronic fatigue syndrome (CFS) is characterized by severe fatigue and a reduction in activity levels. The purpose of this study was to provide an overview of design, reliability, and validity of the CFS Activities and Participation Questionnaire (CFS-APQ).

The CFS-APQ was constructed based on a retrospective analysis of the Karnofsky Performance Status Questionnaire and the Activities of Daily Living Questionnaire (n = 141). In a reliability study of 34 participants the test-retest reliability coefficient of the CFS-APQ was 0.95. In two different studies, the Cronbach alpha coefficient for internal consistency varied between 0.87 (n = 88) and 0.94 (n = 47). The CFS-APQ was administered to 47 patients who listed 183 activities that had become difficult due to their chronic symptoms, and 157 (85.8%) answers matched the content of the CFS-APQ.

The outcome of a cross-sectional study (n = 88) studying the correlations between the Medical Outcomes Short Form 36 Health Status Survey subscale scores and the CFS-APQ supported the validity of the CFS-APQ. The CFS-APQ scores correlated with a behavioural assessment of the patients’ performance of activities encompassed by the questionnaire (r = 0.29-0.55; n = 63), and correlated with exercise capacity parameters (r = 0.26-0.39; n = 77) obtained during a maximal exercise capacity stress test. Finally, the CFS-APQ correlated with visual analogue scales for pain (r = 0.51) and fatigue (r = 0.50; n = 47).

It is concluded that the CFS-APQ generates reliable and valid data, and can be used as a clinical measure of disease severity in patients with CFS. Future studies should aim at examining the sensitivity of the CFS-APQ.

 

Source: Nijs J, Vaes P, De Meirleir K. The Chronic Fatigue Syndrome Activities and Participation Questionnaire (CFS-APQ): an overview. Occup Ther Int. 2005;12(2):107-21. http://www.ncbi.nlm.nih.gov/pubmed/16136868

 

Chronic fatigue syndrome, exercise, cortisol and lymphadenopathy

Dear Sir,

As in the past [1], the effects of exercise in the treatment of chronic fatigue syndrome (CFS) are conflicting. Indeed, while Powell et al. [2], in 2004, reported that graded exercise was beneficial to CFS patients, Black et al. [3] have lately written that ‘overall mood, muscle pain intensity, and time spent each day with fatigue worsened following increased activity’ [3] in CFS patients, despite the fact that their increase in daily physical activity was rather moderate (28%) [3]. The virtually opposite effects of exercise in different groups of CFS patients [1–3] may reflect their different cortisol levels [1], which, just as occurred some years ago [1], continue to be contradictory. For example, Inder et al. [4], in March 2005, reported that cortisol levels were normal in their patients with CFS, whereas Segal et al. [5], in the same month, reported that their subjects with CFS had hypocortisolism.

Considering that most features of CFS, such as ‘debilitating fatigue, an abrupt onset precipitated by a stressor, feverishness, arthralgias, myalgias, adenopathy, postexertional fatigue, exacerbation of allergic responses, and disturbances in mood and sleep are all characteristic of glucocorticoid insufficiency’ [6], it is not surprising that hypocortisolism has been convincingly shown to be implicated in the pathophysiology of CFS [7]. Therefore, especially the postexertional fatigue caused by glucocorticoid insufficiency [6] strongly suggests that exercise could be of benefit to CFS patients with high [1] or normal cortisol levels [4], whereas it could be harmful to CFS patients with hypocortisolism [1, 5, 6]. Unfortunately, because of the misleading coexistence of quite different diagnostic criteria for CFS [1], it is difficult to predict the patients with CFS who are more likely to have hypocortisolism and which would worsen with exercise. However, it is arguable that the presence or absence of lymphadenopathy [8], which is a sign of hypocortisolism [6, 9] and is one of the 43 clinical features that CFS shares with Addison’s disease [10–12], could reliably discriminate CFS patients who may worsen with exercise from those who may improve with it. Indeed, lymphadenopathy, unlike other symptoms of CFS [11, 12], many of which are non-specific and can also be found in depression and other affective disorders [11, 12], is far from being common in physical diseases and is absent in psychiatric conditions.

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Source: Baschetti R. Chronic fatigue syndrome, exercise, cortisol and lymphadenopathy. J Intern Med. 2005 Sep;258(3):291-2. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2796.2005.01526.x/full (Full article)

 

Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study

Abstract:

There have been many epidemiological and clinical researches on chronic fatigue (CF) and chronic fatigue syndrome (CFS) since the 1990s, but such studies have been quite limited in Korea. The aim of this study was to investigate the point prevalence of CF and CFS in patients who visited community-based eight primary care clinics in Korea. The study subjects were 1,648 patients aged 18 yr and over who visited one of eight primary care clinics in Korea between the 7th and 17th of May 2001. The physicians determined the status of the subjects through fatigue-related questionnaires, medical history, physical examination, and laboratory tests. The subjects were categorized into no fatigue, prolonged fatigue, CF and then CF were further classified to medically explained CF (Physical CF and Psychological CF) and medically unexplained CF (CFS and idiopathic chronic fatigue). The point prevalence of CF and CFS were 8.4% (95% CI 7.1-9.7%) and 0.6% (95% CI 0.2-1.0%). Medically explained CF was 80.5% of CF, of which 57.1% had psychological causes. The clinical characteristics of CFS were distinguished from explained CF. CF was common but CFS was rare in community-based primary care settings in Korea.

 

Source: Kim CH, Shin HC, Won CW. Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study. J Korean Med Sci. 2005 Aug;20(4):529-34. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2782143/ (Full article)

 

CFSUM1 and CFSUM2 in urine from patients with chronic fatigue syndrome are methodological artefacts

Abstract:

McGregor et al. reported increased levels of an unidentified urinary compound (CFSUM1) in patients with chronic fatigue syndrome (CFS), with reduced excretion of another unidentified compound (CFSUM2), and suggested the possibility of chemical or metabolic ‘markers’ for CFS. The identity of CFSUM1 as reported was erroneous and the identities of these compounds have remained unknown until now.

Urine samples were obtained from 30 patients with ME/CFS, 30 age- and sex-matched healthy controls, 20 control patients with depression and 22 control patients with rheumatoid arthritis. Samples were prepared using the published methods of McGregor et al. to produce heptafluorobutyryl-isobutyl derivatives of urinary metabolites. Alternative preparations utilised isopropyl, n-butyl and trifluoroacetyl derivatives. These were separated and identified using gas chromatography-mass spectrometry.

CFSUM2 was identified as being partially derivatised [isobutyl ester-mono-heptafluorobutyryl (HFB)] serine. CFSUM1 was identified as partially derivatised pyroglutamic acid, being the isobutyl ester without formation of a HFB derivative.

Both CFSUM1 and CFSUM2 are artefacts of the sample preparation procedure and previously reported quantitative abnormalities of CFSUM1 and CFSUM2 in urine from patients with ME/CFS are also artefactual. Pyroglutamic acid may be of primarily dietary origin. The methods used cannot provide reliable qualitative or quantitative data on urinary metabolites. No clinical or biochemical significance can be drawn between these compounds in ME/CFS or any other clinical conditions.

 

Source: Chalmers RA, Jones MG, Goodwin CS, Amjad S. CFSUM1 and CFSUM2 in urine from patients with chronic fatigue syndrome are methodological artefacts. Clin Chim Acta. 2006 Feb;364(1-2):148-58. Epub 2005 Aug 10. http://www.ncbi.nlm.nih.gov/pubmed/16095585

 

The definition of disabling fatigue in children and adolescents

Abstract:

BACKGROUND: Disabling fatigue is the main illness related reason for prolonged absence from school. Although there are accepted criteria for diagnosing chronic fatigue in adults, it remains uncertain as to how best to define disabling fatigue and Chronic Fatigue Syndrome (CFS) in children and adolescents. In this population-based study, the aim was to identify children who had experienced an episode of disabling fatigue and examine the clinical and demographic differences between those individuals who fulfilled a narrow definition of disabling fatigue and those who fulfilled broader definitions of disabling fatigue.

METHODS: Participants (aged 8-17 years) were identified from a population-based twin register. Parent report was used to identify children who had ever experienced a period of disabling fatigue. Standardised telephone interviews were then conducted with the parents of these affected children. Data on clinical and demographic characteristics, including age of onset, gender, days per week affected, hours per day spent resting, absence from school, comorbidity with depression and a global measure of impairment due to the fatigue, were examined. A narrow definition was defined as a minimum of 6 months disabling fatigue plus at least 4 associated symptoms, which is comparable to the operational criteria for CFS in adults. Broader definitions included those with at least 3 months of disabling fatigue and 4 or more of the associated symptoms and those with simply a minimum of 3 months of disabling fatigue. Groups were mutually exclusive.

RESULTS: Questionnaires were returned by 1468 families (65% response rate) and telephone interviews were completed on 99 of the 129 participants (77%) who had experienced fatigue. There were no significant differences in demographic and clinical characteristics or levels of impairment between those who fulfilled the narrower definition and those who fulfilled the broader definitions. The only exception was the reported number of days per week that the child was affected by the fatigue. All groups demonstrated evidence of substantial impairment associated with the fatigue.

CONCLUSION: Children and adolescents who do not fulfil the current narrow definition of CFS but do suffer from disabling fatigue show comparable and substantial impairment. In primary care settings, a broader definition of disabling fatigue would improve the identification of impaired children and adolescents who require support.

 

Source: Fowler T, Duthie P, Thapar A, Farmer A. The definition of disabling fatigue in children and adolescents. BMC Fam Pract. 2005 Aug 9;6:33. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1192794/ (Full article)

 

Illnesses you have to fight to get: facts as forces in uncertain, emergent illnesses

Abstract:
Chronic fatigue syndrome and multiple chemical sensitivity are two clusters of illnesses that are pervaded by medical, social and political uncertainty. This article examines how facts are talked about and experienced in struggles over these emergent, contested illnesses in the US. Based principally on a large archive of internet newsgroup postings, and also on fieldwork and on published debates, it finds that (1) sufferers describe their experiences of being denied healthcare and legitimacy through bureaucratic categories of exclusion as dependent upon their lack of biological facts; (2) institutions manage these exclusions rhetorically through exploiting the open-endedness of science to deny efficacy to new facts; (3) collective patient action responds by archiving the systematic nature of these exclusions and developing counter-tactics. The result is the maintenance of these very expensive struggles for all involved.

 

Source: Dumit J. Illnesses you have to fight to get: facts as forces in uncertain, emergent illnesses. Soc Sci Med. 2006 Feb;62(3):577-90. Epub 2005 Aug 8. http://www.ncbi.nlm.nih.gov/pubmed/16085344