A systematic review describing the prognosis of chronic fatigue syndrome

AIM: To perform a systematic review of studies describing the prognosis of chronic fatigue (CF) and chronic fatigue syndrome (CFS) and to identify occupational outcomes from such studies. METHOD: A literature search was used to identify all studies describing the clinical follow-up of patients following a diagnosis of CF or CFS. The prognosis is described in terms of the proportion of individuals improved during the period of follow-up. Return to work, other medical illnesses and death as outcomes are also considered, as are variables which may influence prognosis. RESULTS: Twenty-eight articles met the inclusion criteria and, for the 14 studies of subjects meeting operational criteria for CFS, the median full recovery rate was 5% (range 0-31%) and the median proportion of patients who improved during follow-up was 39.5% (range 8-63%). Less fatigue severity at baseline, a sense of control over symptoms and not attributing illness to a physical cause were all associated with a good outcome. Return to work at follow-up ranged from 8 to 30% in the three studies that considered this outcome. CONCLUSIONS: Full recovery from untreated CFS is rare. The prognosis for an improvement in symptoms is less gloomy. This review looks at the course of CF/CFS without systematic intervention. However, there is increasing evidence for the effectiveness of cognitive behavioural and graded exercise therapies. Medical retirement should be postponed until a trial of such treatment has been given.     

Unloading the trunk: neurasthenia, CFS and race

The aetiologies of both chronic fatigue syndrome (CFS) and its predecessor neurasthenia, have been linked to technological advances in 'developed' countries. This paper discusses how this has led to a form of race thinking within discussions about fatigue which has persisted for more than a century. We review the historical development of this race thinking from neurasthenia to CFS and describe how it is manifested in both the lay- and medical literature. We also review the epidemiological literature on CFS and ethnicity to better understand the relatively low percentage of non-white patients seen in tertiary referral clinics for CFS. The aim of this paper is to act as a starting point for a debate on race and CFS.     

Treatments for chronic fatigue syndrome

AIMS: To review studies evaluating the treatment of chronic fatigue and chronic fatigue syndrome, to describe predictors of response to treatment and to discuss the role of the occupational health physician. METHODS: A literature search was carried out using Medline and PsychInfo. RESULTS: Studies evaluating cognitive behaviour therapy, graded exercise therapy, pharmacological interventions (e.g. antidepressants and corticosteroids), immunological interventions and nutritional supplements were reviewed. The most promising results have been found with cognitive behaviour therapy and graded exercise therapy, and some predictors of outcome have been identified. Most of the other interventions were evaluated in just one or two studies and therefore evidence is insufficient to draw firm conclusions. CONCLUSIONS: By applying the models of fatigue that form the bases for cognitive behaviour therapy and graded exercise therapy, occupational health physicians may play an important role in helping the patients with chronic fatigue syndrome to reduce their symptoms, improve their functioning and return to work.     

Psychological workload and body weight: is there an association? A review of the literature

BACKGROUND: According to Karasek's Demand/Control Model, workload can be conceptualized as job strain, a combination of psychological job demands and control in the job. High job strain may result from high job demands combined with low job control. Aim To give an overview of the literature on the association between obesity and psychological workload. METHOD: We carried out a review of the associations between psychological workload and body weight in men and women. In total, 10 cross-sectional studies were identified. RESULTS: The review showed little evidence of a general association between psychological workload and body mass index. Only weak positive associations were found, and only between elements of psychological workload and overall body weight. For body fat distribution, two out of three studies showed a positive association in men, but the associations became insignificant after adjustment for education. For women, there was no evidence of a consistent association. CONCLUSION: The reviewed articles were not supportive of any associations between psychological workload and either general or abdominal obesity. Future epidemiological studies in this field should be prospective or experimental, and should examine how chronic work stress affects eating and to what extent initial body weight is a predictor for individual differences in perceived psychological workload.     

Chronic fatigue syndrome and occupational health

Chronic fatigue syndrome (CFS) is a controversial conditionthat many occupational physicians find difficult to advise on.In this article we review the nature and definition of CFS,the principal aetiologic hypotheses and the evidence concerningprognosis. We also outline a practical approach to patient assessment,diagnosis and management. The conclusions of this review arethen applied to the disability discrimination field. The implicationsof the new UK occupational health legislation are also examined.Despite continuing controversy about the status, aetiology andoptimum management of CFS, we argue that much can be done toimprove the outcome for patients with this condition. The mosturgent needs are for improved education and rehabilitation,especially in regard to employment. Occupational physiciansare well placed to play an important and unique role in meetingthese needs.     

The adoption of chronic fatigue syndrome/myalgic encephalomyelitis case definitions to assess prevalence: a systematic review

PurposePrevalence estimates have been based on several case definitions of chronic fatigue syndrome (CFS). The purpose of this work is to provide a rigorous overview of their application in prevalence research.MethodsA systematic review of primary studies reporting the prevalence of CFS since 1990 was conducted. Studies were summarized according to study design, prevalence estimates, and case definition used to ascertain cases.ResultsThirty-one studies were retrieved, and eight different case definitions were found. Early estimates of CFS prevalence were based on the 1988 Centers for Disease Control and Prevention, Australian, and Oxford. The 1994 Centers for Disease Control and Prevention, however, has been adopted internationally, as a general standard. Only one study has reported prevalence according to the more recent, Canadian Consensus Criteria. Additional estimates were also found according to definitions by Ho-Yen, the 2005 Centers for Disease Control and Prevention empirical definition, and an epidemiological case definition.ConclusionsAdvances in clinical case definitions during the past 10 years such as the Canadian Consensus Criteria have received little attention in prevalence research. Future assessments of prevalence should consider adopting more recent developments, such as the newly available International Consensus Criteria. This move could improve the surveillance of more specific cases found within CFS.     

Low back pain among Iranian industrial workers

BACKGROUND: Most epidemiological data concerning low back pain (LBP) are from high-income countries and there is very little information about LBP in the working population in developing countries. OBJECTIVES: To determine the prevalence of LBP in Iranian industrial workers. To explore associations between LBP and physical and psychosocial factors at work, as well as lifestyle factors. METHODS: Cross-sectional study of the largest car-manufacturing group in Iran. The prevalence of LBP, work exposures and lifestyle factors were recorded using the standardized Nordic questionnaire for analysis of musculoskeletal symptoms. Demographic data and lifestyle factors (age, sex, education, weight, work experience, smoking and fitness training) were also collected. RESULTS: Of the 18,031 employees, 78% participated. The majority of subjects in this study population were young males (<30 years) and a small proportion was female (4%). The 1-year prevalence of self-reported LBP in this Iranian industrial population was 21% (20% males and 27% females). The prevalence rate of absence due to LBP was 5% per annum. The multiple logistic regression models indicated that the following remained risk indicators for LBP in the previous 12 months: increasing age, no regular exercise, heavy lifting, repetitive work and monotonous work. CONCLUSION: LPB is a common problem in the working population even in a developing country. Age and gender as well as certain work-related physical and psychosocial factors influenced the prevalence of LBP but the differences between different categories of workers were small.     

Occupational groups at risk of voice disorders: a review of the literature

BACKGROUND: Occupational voice health is becoming more important as more people rely on their voices for their work. A number of studies have identified certain occupational groups at increased risk of developing occupational voice disorders, namely teachers, singers and aerobics instructors. Aim The paper aims to review the literature on occupational groups at risk of voice disorders and identify areas for future research. METHOD: A literature review of key databases using key words such as 'occupational', 'voice health', 'voice loss', 'dysphonia' and 'work related' was undertaken. RESULTS: The review identified case reports, studies of attendees at hospital voice clinics and a few cross-sectional studies of occupational groups in the workplace. There were no longitudinal studies found or intervention studies looking at reduction of risk. CONCLUSION: Further research on occupational voice disorders needs to be based in the workplace, and to look at the risk factors for the development of voice problems and for the efficacy of controls.     

Chronic fatigue among bank workers in Brazil

The present study examines the prevalence of chronic fatigue (CF) among bank workers in Brazil and possible associations with gender and working conditions. The study sample included all 735 workers from the department of data processing of a state bank. CF was assessed using the Chalder Fatigue Scale. Working conditions and socio-demographic, socio-economic and psychosocial factors at work were analysed. Psychiatric symptoms were measured with the SRQ-20. The overall estimate of the prevalence of CF was 8.7% [95% confidence intervals (95% CI) = 6.4-10.9%]: 7.8% (95% CI = 5.5-10.7%) among men and 11.0% (95% CI = 6.7-16.9%) among women. The male-female difference was not statistically significant, even after adjusting for minor psychiatric disorders. The overall prevalence of CF without minor psychiatric disorders was 4.5% (95% CI = 2.7-6.3%): 3.9% (95% CI = 1.9-5.9%) among men and 6.4% (95% CI = 2.0-10.1%) among women. In the final model, risk factors for CF were fast work speed [odds ratio (OR) = 3.5], dissatisfaction at work (OR = 3.1), minor psychiatric disorders (OR = 6.8), and medium (OR = 1.8) and heavy domestic workload (OR = 12.0). CF is common among these bank workers and is associated with psychosocial factors at work. Particularly among women, domestic workload, marital status and the presence of young children were associated with CF in the stratified analysis. Domestic workload may add physical and mental stress, putting employees at risk for CF from overload, or CF may cause workers to perceive domestic work as heavy.     

慢性疲劳综合征精神情志症状的文献研究

目的通过文献研究分析慢性疲劳综合征精神情志特点与预后转归的关系。方法对慢性疲劳综合征(chronic fa-tigue syndrome,CFS)的基本概念、诊断标准、流行病学特征的文献资料以及精神情志因素与慢性疲劳综合征病程及预后的文献资料进行研究整理,评价常用的几种CFS症状测评量表,分析这些量表在评估CFS患者精神情志特点上的异同。结果文献研究发现,CFS患者普遍存在大量精神情志症状。结论有必要进行临床大样本调查,系统分析慢性疲劳综合征精神情志特点与预后转归的相关性,为进一步明确CFS情志疗法提供理论和临床依据。     

Systematic review of studies of productivity loss due to rheumatoid arthritis

BACKGROUND: Rheumatoid arthritis (RA) is a chronic, debilitating disease with a significant impact on workplace productivity. AIM: To perform a systematic review of studies of the relationship between RA and reduced workplace productivity. METHODS: Screening of 307 titles identified in bibliographic database searches resulted in 38 articles subject to systematic review. Productivity loss was expressed by three different measures: work disability, work loss (synonymous with absenteeism or short-term sick leave) and work limitation (reduction in productivity while present at work). RESULTS: A median of 66% (range 36-84%) of employed RA subjects experienced work loss due to RA in the previous 12 months, for a median duration of 39 days (range 7-84 days). The times from RA diagnosis until a 50% probability of being work disabled varied from 4.5 to 22 years. In inception cohort studies, the baseline variables consistently predictive of subsequent work disability were a physically demanding work type, more severe RA and older age. CONCLUSIONS: RA-related work-disability rates were similar in the USA and European countries. An apparent decrease in the prevalence of RA-related work disability since the 1970s may be related to a decrease in physically demanding work rather than to epidemiologic changes in RA. The majority of the literature addresses permanent disability and temporary work loss; none of the studies reviewed reported the effect of RA on presenteeism, i.e. work limitation from the employer perspective, and there are few published studies of the effectiveness of disease-modifying anti-rheumatic drugs in reducing work-related productivity loss.     

Work with pesticides and organophosphate sheep dips

Pesticides are an important hazard in agriculture. In developed countries their use is strictly regulated. Risk assessment for new pesticides includes comparison of the potential exposures of spray operators and other farm workers with a reference value. Usually, this is derived from toxicological studies in animals with allowance for the uncertainties in extrapolating between and within species. Older pesticides undergo periodic reviews, for which epidemiological data may also be available. Unintentional fatal poisoning by pesticides is extremely rare in Britain. Documented reports of non-fatal acute poisoning are also uncommon, but there may be substantial under-ascertainment of minor incidents. Pesticides have been linked with various chronic diseases, but few associations have been clearly established. A particular concern recently in Britain has been the possibility that organophosphate insecticides can cause chronic neuropsychiatric illness.     

Mobile phone use and subjective symptoms. Comparison of symptoms experienced by users of analogue and digital mobile phones

In 1995 many people reported symptoms such as headaches, feelings of discomfort, warmth behind/around or on the ear and difficulties concentrating while using mobile phones. The number of complaints was higher for people using the digital (GSM) system, i.e. with pulse modulated fields, than for those using the analogue (NMT) system. Our main hypothesis was that GSM users experience more symptoms than NMT users. An epidemiological investigation was initiated including 6379 GSM users and 5613 NMT 900 users in Sweden, and 2500 from each category in Norway. The adjusted odds ratio did not indicate any increased risk for symptoms for GSM users compared with NMT 900 users. Our hypothesis was therefore disproved. However, we observed a statistically significant lower risk for sensations of warmth on the ear for GSM users compared with NMT 900 users. The same trend was seen in Norway for sensations of warmth behind/around the ear and in Sweden for headaches and fatigue. Factors distinguishing the two systems (radio frequency emission, phone temperatures and various ergonomic factors) may be responsible for these results, as well as for a secondary finding: a statistically significant association between calling time/number of calls per day and the prevalence of warmth behind/around or on the ear, headaches and fatigue.     

Prevalence of fatigue among commercial pilots

BACKGROUND: Short-haul pilots have largely been neglected in studies of fatigue, sleep loss and circadian disruption created by flight operations, but anecdotal evidence from pilots suggests that with the increasing amount of low-cost air travel, commercial pilots working short-haul operations may be becoming seriously fatigued. AIMS: This study attempted to ascertain how much subjective fatigue short-haul pilots reported, and makes comparisons between low-cost and scheduled airline pilots. METHODS: Pilots completed anonymous questionnaires (encompassing aviation factors, flight experience and a fatigue scale) posted on the Professional Pilots' Rumours Network website. RESULTS: Data were collected from 162 short-haul pilots and statistical adjustment for operational factors was made. Seventy-five percent reported severe fatigue and 81% reported the fatigue to be worse than 2 years ago. Eighty percent considered their thought processes were reduced while flying. Severe fatigue was reported more frequently by low-cost airline pilots than scheduled airline pilots (P = 0.05) and fatigue ratings were higher in this group (P = 0.03). Pilots who reported regularly flying into their 'discretion' hours had lower physical and psychological health, and overall fatigue scores, and poorer self-rated general health. Flying into discretion time occurred no more frequently in low-cost airline pilots than scheduled airline pilots. CONCLUSIONS: Identifiable fatigue problems are reported by short-haul pilots, but this cannot be attributed solely to the work schedules of low-cost airlines as regular use of discretion time appears to be associated with fatigue regardless of airline.     

Role of dietary modification in alleviating chronic fatigue syndrome symptoms: a systematic review

Objective: To review the evidence for the role of dietary modifications in alleviating chronic fatigue syndrome symptoms. Methods: A systematic literature review was guided by PRISMA and conducted using Scopus, CINAHL Plus, Web of Science and PsycINFO scientific databases (1994–2016) to identify relevant studies. Twenty‐two studies met the inclusion criteria, the quality of each paper was assessed and data extracted into a standardised tabular format. Results: Positive outcomes were highlighted in some included studies for polyphenol intakes in animal studies, D‐ribose supplementation in humans and aspects of symptom alleviation for one of three polynutrient supplement studies. Omega three fatty acid blood levels and supplementation with an omega three fatty acid supplement also displayed positive outcomes in relation to chronic fatigue syndrome symptom alleviation. Conclusions: Limited dietary modifications were found useful in alleviating chronic fatigue syndrome symptoms, with overall evidence narrow and inconsistent across studies. Implications for public health: Due to the individual and community impairment chronic fatigue syndrome causes the population, it is vital that awareness and further focused research on this topic is undertaken to clarify and consolidate recommendations and ensure accurate, useful distribution of information at a population level.     

The prognosis of different fatigue diagnostic labels: a longitudinal survey

BACKGROUND: Several different diagnostic labels exist for the fatigue syndromes, including chronic fatigue syndrome (CFS), myalgic encephalomyelitis (ME) and postviral fatigue syndrome (PVFS). An allied condition is fibromyalgia. No study has examined prognostic differences across these different labels. OBJECTIVE: To compare the prognoses of patients labelled with different fatigue syndromes in primary care. METHODS: We performed a longitudinal survey, using electronic records from the General Practice Research Database. All 18,122 patients diagnosed by their GP with a fatigue syndrome from 1988-2001 with a minimum of one year of records after diagnosis were collated into four groups: CFS, ME, PVFS and fibromyalgia. CFS and ME were combined for the main analysis as no code for CFS was available until 1995. The length of illness was calculated as the interval between the diagnosis and the last recorded fatigue symptom, expressed as days per year, to account for differing lengths of record after diagnosis. RESULTS: Patients with CFS/ME combined had a worse prognosis (median length of illness 80 days per year; interquartile range 0-242) than fibromyalgia (51; 0-244) or PVFS 0 (0-108), a significant difference, P < 0.001. In a subgroup analysis, ME had a worse prognosis (median length of illness in days per year 106; interquartile range 0-259) than CFS (33; 0-170), P < 0.001, in spite of a better course before diagnosis. Secondary outcome measures were consistent with these results. CONCLUSION: There were important differences in outcome between the various fatigue labels, with ME having the worst prognosis and PVFS the best. This could be an adverse effect of the label ME itself. Alternatively, patients who are destined to have a worse prognosis may preferentially attract the ME label. Our data support the first interpretation.     

Fatigue in chronic fatigue syndrome: a discourse analysis of women's experiential narratives

Chronic fatigue syndrome (CFS) is a debilitating condition. Approximately 75% of sufferers are women. The etiology of CFS is debated, but remains inconclusive. "Fatigue" is ill defined and conceptually problematic. The international multidisciplinary literature on CFS reveals a paucity of studies on women. Qualitative research to analyze women's discourses on CFS is virtually absent. Eleven New Zealand women of European descent with experience of CFS were interviewed in depth. Within the complex facets of CFS, this article reports specifically on an analysis of discourses on "fatigue." The predominant theme that emerged was that fatigue is articulated as "lack" or absence, which is not representable as an identifiable entity in biomedical terms. Parallels with chronic pain are briefly drawn. We conclude that approaches to CFS must respond to the diverse and complex constructions of the experience of fatigue evident in women's narratives.     

Adolescent Offspring of Mothers With Chronic Fatigue Syndrome

PurposeThe goal of this study was to determine whether adolescent offspring of mothers with chronic fatigue syndrome (CFS) have higher prevalence of CFS and report more fatigue, greater pain sensitivity, more sleep problems, and poorer cardiopulmonary fitness in comparison with offspring with no exposure to maternal CFS.MethodsA total of 26 adolescent offspring of 20 mothers diagnosed with CFS were compared with 45 adolescent offspring of 30 age-matched healthy control mothers. Study measures included structured interviews and medical and laboratory examinations for CFS; tender point examination; maximum oxygen uptake and perceived exertion; dolorimetry pain ratings; and questionnaires on fatigue severity and sleepiness.ResultsIn comparison with offspring of healthy mothers, those exposed to mothers with CFS reported higher prevalence of fatigue of at least 1-month duration (23% vs. 4%), fatigue of 6 months or longer (15% vs. 2%), and met criteria for CFS (12% vs. 2%), although these differences only approached statistical significance. CFS and healthy mothers differed on almost all study outcomes, but offspring groups did not differ on measures of current fatigue severity, pain sensitivity, sleep, mean number of tender points, and cardiopulmonary fitness.ConclusionsThe higher prevalence of fatiguing states in offspring of CFS mothers, despite the lack of statistical significance, suggests that familial factors may potentially play a role in developing chronically fatiguing states. Alternately, perturbations in pain sensitivity and cardiopulmonary fitness may be consequences of CFS. Future studies should focus on examining the impact of maternal CFS and associated disability on psychosocial functioning of offspring.