Category: Epidemiology

Chronic fatigue syndrome: occupation, medical utilization, and subtypes in a community-based sample

Abstract:

Most studies of chronic fatigue syndrome (CFS) have been based on patients recruited from primary or tertiary care settings. Patients from such settings might not be typical of patients in the general population. The present investigation involved examining individuals with CFS from a community-based study. A random sample of 18,675 respondents in Chicago was first interviewed by telephone. A group of individuals with chronic fatigue accompanied by at least four minor symptoms associated with CFS were given medical and psychiatric examinations. From this sample, a physician review group diagnosed individuals with CFS.

Those diagnosed with CFS were subclassified based on a variety of categories, including duration of illness, mode of illness onset, and presence or absence of a stressful life event directly preceding onset. In addition, we examined medical utilization among those diagnosed with CFS, as well as whether individuals with CFS were disproportionately represented in health care professions. Important differences emerged on measures of sociodemographics, symptoms, and functional disability. The implications of these findings and others are discussed.

 

Source: Jason LA, Taylor RR, Kennedy CL, Song S, Johnson D, Torres S. Chronic fatigue syndrome: occupation, medical utilization, and subtypes in a community-based sample. J Nerv Ment Dis. 2000 Sep;188(9):568-76. http://www.ncbi.nlm.nih.gov/pubmed/11009329

 

Developing case definitions for symptom-based conditions: the problem of specificity

Symptom-based conditions are postulated organic diseases that are characterized primarily by chronic physical (somatic) symptoms (1, 2). Contemporary conditions associated with multisystem complaints are generally referred to as chronic fatigue syndrome, fibromyalgia, multiple chemical sensitivities, silicone associated atypical rheumatic disease, sick building syndrome, and most recently, Gulf War syndrome (table 1). Possibly related disorders that will not be considered in the following analysis include epidemic neuromyasthenia, hyperventilation syndrome, reactive hypoglycemia, post-lyme disease syndrome, and irritable bowel syndrome (3).

Although the need to consistently define symptombased conditions has been repeatedly emphasized, there has been limited progress in establishing widely accepted diagnostic criteria (1,4). Based on reports in English-language publications, symptom-based conditions were analyzed to determine why it has been difficult to develop case definitions of unique diseases.

You can read the rest of this article here: http://epirev.oxfordjournals.org/content/20/2/148.long

 

Source: Hyams KC. Developing case definitions for symptom-based conditions: the problem of specificity. Epidemiol Rev. 1998;20(2):148-56. http://epirev.oxfordjournals.org/content/20/2/148.long (Full article)

Prevalence of chronic fatigue syndrome in a community population in Japan

Abstract:

In order to know the prevalence of chronic fatigue syndrome (CFS) in a community population in Japan, we analyzed data from a population-based interview survey. Two cases out of 137 respondents experienced chronic fatigue during a period of nine months, suffered from 50% or more reduction of daily activity due to fatigue and had no other physical or psychiatric diagnosis. Both of the two cases fulfilled the 1994 Centers for Disease Control (CDC) criteria and the British criteria. The point and nine-month prevalence rates of CFS were both 1.5% (95% confidence intervals, 0.4-5.2%). None fulfilled the 1989 CDC criteria for CFS. The prevalence rate of CFS was higher than those in previous studies in the Western countries, suggesting a need for future research on cross-cultural differences in the definition, prevalence and symptomatology of CFS.

 

Source: Kawakami N, Iwata N, Fujihara S, Kitamura T. Prevalence of chronic fatigue syndrome in a community population in Japan. Tohoku J Exp Med. 1998 Sep;186(1):33-41. https://www.jstage.jst.go.jp/article/tjem/186/1/186_1_33/_article (Full article)

 

Estimating the prevalence of chronic fatigue syndrome among nurses

Abstract:

The present study assessed the prevalence of chronic fatigue syndrome (CFS) in a sample of nurses. There is a paucity of studies on the prevalence of CFS in healthcare professionals.

Two samples of nurses were recruited through mailed questionnaires. Data were collected on demographic characteristics and symptoms. In addition from the sample, those nurses with CFS-like symptoms were more comprehensively evaluated using a structured clinical interview and reviewing their medical records. A physician review team estimated the prevalence of CFS to be 1,088 per 100,000.

These findings suggest that nurses might represent a high-risk group for this illness, possibly due to occupational stressors such as exposure to viruses in the work setting, stressful shift work that is disruptive to biologic rhythms, or to other possible stressors in the work settings (e.g., accidents).

 

Source: Jason LA, Wagner L, Rosenthal S, Goodlatte J, Lipkin D, Papernik M, Plioplys S, Plioplys AV. Estimating the prevalence of chronic fatigue syndrome among nurses. Am J Med. 1998 Sep 28;105(3A):91S-93S. http://www.ncbi.nlm.nih.gov/pubmed/9790488

 

The epidemiology of chronic fatigue in San Francisco

Abstract:

Despite considerable research on chronic fatigue syndrome (CFS) and conditions associated with unexplained chronic fatigue (CF), little is known about their prevalence and demographic distribution in the population. The present study describes the epidemiology and characteristics of self-reported CF and related conditions in a diverse urban community.

The study used a cross-sectional telephone screening survey of households in San Francisco, followed by interviews with fatigued and nonfatigued residents. Respondents who appeared to meet case definition criteria for CFS, based on self-reported fatigue characteristics, symptoms, and medical history, were classified as CFS-like cases. Subjects who reported idiopathic chronic fatigue (ICF) that did not meet CFS criteria were classified as ICF-like cases.

Screening interviews were completed for 8,004 households, providing fatigue and demographic information for 16,970 residents. Unexplained CF was extremely rare among household residents <18 years of age, but was reported by 2% of adult respondents. A total of 33 adults (0.2% of the study population) were classified as CFS-like cases and 259 (1.8%) as ICF-like cases. Neither condition clustered within households.

CFS- and ICF-like illnesses were most prevalent among women and persons with annual household incomes below $40,000, and least prevalent among Asians. The prevalence of CFS-like illness was elevated among African Americans, Native Americans, and persons engaged in clerical occupations. Although CFS-like cases were more severely ill than those with ICF-like illness, a similar symptom pattern was observed in both groups.

In conclusion, conditions associated with unexplained CF occur in all sociodemographic groups but appear to be most prevalent among women, persons with lower income, and some racial minorities.

 

Source: Steele L, Dobbins JG, Fukuda K, Reyes M, Randall B, Koppelman M, Reeves WC. The epidemiology of chronic fatigue in San Francisco. Am J Med. 1998 Sep 28;105(3A):83S-90S. http://www.ncbi.nlm.nih.gov/pubmed/9790487

 

Cancer and a fatiguing illness in Northern Nevada–a causal hypothesis

Abstract:

PURPOSE: We investigated the possibility that chronic fatigue syndrome (CFS) predisposes to cancer by comparing the cancer pattern in an area in northern Nevada, where an outbreak of a fatiguing illness, which included cases of CFS, was reported, to an area in southern Nevada, where no such illness was reported.

METHODS: Data from the computerized Nevada Cancer Registry were utilized to compare incidence rates of four malignancies–brain cancer, non-Hodgkin lymphoma (NHL), lung cancer, and breast cancer–in Washoe and Lyon Counties, where an unexplained fatiguing illness was reported during 1984-86, with comparably sized Clark County, where no such illness was reported.

RESULTS: Higher incidences of NHL and primary brain tumors were noted in the two northern Nevada counties (Washoe and Lyon) in 1986 and 1987 respectively, compared to the southern Nevada (Clark) county. Similar patterns were not seen for breast or lung cancer.

CONCLUSIONS: This study provides a model for investigating the possible predisposition of CFS patients to develop cancer using other cohorts, but it is currently premature to accept such a link at this time.

 

Source: Levine PH, Fears TR, Cummings P, Hoover RN. Cancer and a fatiguing illness in Northern Nevada–a causal hypothesis. Ann Epidemiol. 1998 May;8(4):245-9. http://www.ncbi.nlm.nih.gov/pubmed/9590603

 

Outcomes of occupational stressors on nurses: chronic fatigue syndrome–related symptoms

Abstract:

Considering the types and number of occupational stressors involved in caring for patients, nurses may represent a population at high risk for physical illnesses.

A sample of 3400 nurses who belong to a statewide or a national nurses organization were randomly chosen for participation. Of this group, 202 reported 6 months or more of debilitating fatigue and completed a three-page questionnaire assessing symptoms related to chronic fatigue syndrome (CFS) and comorbid medical conditions. This group (N = 202) was mailed a follow-up questionnaire 1 year later that reassessed symptoms of CFS and occupational stressors.

Many sampled nurses reported a high degree of occupationally related stress but did not report CFS symptoms; however, perceived exposure to the threat of an accident as a nurse and poor physical working conditions were significantly related to symptoms reported. These findings are consistent with previous research.

 

Source: Wagner LI, Jason LA. Outcomes of occupational stressors on nurses: chronic fatigue syndrome–related symptoms. Nursingconnections. 1997 Fall;10(3):41-9. http://www.ncbi.nlm.nih.gov/pubmed/9397874

 

A population-based incidence study of chronic fatigue

Abstract:

BACKGROUND: Most research on syndromes of chronic fatigue has been conducted in clinical settings and is therefore subject to selection biases. We report a population-based incidence study of chronic fatigue (CF) and chronic fatigue syndrome (CFS).

METHODS: Questionnaires assessing fatigue and emotional morbidity were sent to 695 adult men and women who had replied to a postal questionnaire survey 1 year earlier. Possible CFS cases, subjects with probable psychiatric disorder and normal controls were interviewed.

RESULTS: Baseline fatigue score, the level of emotional morbidity and a physical attribution for fatigue were risk factors for developing CF. However, after adjusting for confounding, premorbid fatigue score was the only significant predictor. A minority of CF subjects, all female, had consulted their general practitioner; higher levels of both fatigue and emotional morbidity were associated with consultation. Possible CFS cases reported similar rates of current and past psychiatric disorder to psychiatric controls, but after controlling for fatigue or a diagnosis of neurasthenia the current rates were more similar to those of normal controls. Two new cases of CFS were confirmed.

CONCLUSIONS: Both fatigue and emotional morbidity are integral components of chronic fatigue syndromes. The demographic and psychiatric associations of CFS in clinical studies are at least partly determined by selection biases. Given that triggering and perpetuating factors may differ in CFS, studies that examine the similarities and differences between chronic fatigue syndromes and psychiatric disorder should consider both the stage of the illness and the research setting.

 

Source: Lawrie SM, Manders DN, Geddes JR, Pelosi AJ. A population-based incidence study of chronic fatigue. Psychol Med. 1997 Mar;27(2):343-53. http://www.ncbi.nlm.nih.gov/pubmed/9089827

 

An epidemiologic study of fatigue with relevance for the chronic fatigue syndrome

Abstract:

We surveyed households in four rural Michigan communities to confirm a reported cluster of cases resembling chronic fatigue syndrome (CFS) and to study the epidemiology of fatigue in a rural area. Data were collected from 1698 households. We did not confirm the reported cluster. The prevalence of households containing at least one fatigued person was similar between communities thought to harbor the cluster and communities selected for comparison. Symptoms and features of generic forms of fatigue were very similar to those often attributed to CFS.

 

Source: Fukuda K, Dobbins JG, Wilson LJ, Dunn RA, Wilcox K, Smallwood D. An epidemiologic study of fatigue with relevance for the chronic fatigue syndrome. J Psychiatr Res. 1997 Jan-Feb;31(1):19-29. http://www.ncbi.nlm.nih.gov/pubmed/9201644

 

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