Category: Epidemiology

Descriptive epidemiology of chronic fatigue syndrome based on a nationwide survey in Japan

Abstract:

In order to clarify the epidemiological features of chronic fatigue syndrome (CFS), a nationwide survey was conducted using the Japanese version of the CDC Criteria prepared by the CFS Research Group of Japan. All clinical departments of internal medicine, pediatrics, psychiatry and neurology at university hospitals and at ordinary hospitals with 200 or more beds were surveyed.

Major results were as follows: (1) Period prevalence adjusted for response rate was 0.85 (0.63 for males and 1.02 for females) per 100,000 population during the year 1992; (2) Based on the first and final dates of hospital visits, the prevalences on January 1 of 1992 and 1993 were 0.40 and 0.60 per 100,000 population, respectively, suggesting an increasing trend; (3) Reported new cases during 1992 were 301, and the response adjusted-incidence was estimated to be 0.46 per 100,000 person-years; (4) The proportion of post-infectious CFS cases was 14.8% for both sexes, and tended to be slightly higher among females than males, but was not related to age. Three clusterings of two cases were reported.

 

Source: Minowa M, Jiamo M. Descriptive epidemiology of chronic fatigue syndrome based on a nationwide survey in Japan. J Epidemiol. 1996 Jun;6(2):75-80. https://www.jstage.jst.go.jp/article/jea1991/6/2/6_2_75/_pdf (Full article)

 

Seroepidemiology of chronic fatigue syndrome: a case-control study

Abstract:

We performed serological testing for a large number of infectious agents in 26 patients from Atlanta who had chronic fatigue syndrome (CFS) and in 50 controls matched by age, race, and sex. We did not find any agent associated with CFS. In addition, we did not find elevated levels of antibody to any of a wide range of agents examined. In particular, we did not find elevated titers of antibody to any herpesvirus, nor did we find evidence of enteroviral exposure in this group of patients.

 

Source: Mawle AC, Nisenbaum R, Dobbins JG, Gary HE Jr, Stewart JA, Reyes M, Steele L, Schmid DS, Reeves WC. Seroepidemiology of chronic fatigue syndrome: a case-control study. Clin Infect Dis. 1995 Dec;21(6):1386-9. http://www.ncbi.nlm.nih.gov/pubmed/8749620

 

Cytomegalovirus and Epstein-Barr Virus Infection as a Cause of Chronic Fatigue Syndrome in Travelers to Tropical Countries

Although for research purposes the clinical definition of the chronic fatigue syndrome (CFS) is well established, many aspects of this illness such as its etiology, pathogenesis, and treatment are still unknown. Even the clinical definition is subject to controversy, and although much effort has been expended in the investigation of the clinical aspects of the syndrome, little is known about its epidemiology.

This article considers a cohort of 14 cases that meet the criteria of CFS.The signs and symptoms of CFS in these cases manifested during, or shortly after, a trip to a tropical country.These signs and symptoms appeared to be related to cytomegalovirus (MV) or Epstein-Barr virus infection (EBV).

You can read the full article here: http://jtm.oxfordjournals.org/content/jtm/2/1/41.full.pdf

 

Source: Gascón J, Marcos T, Vidal J, Garcia-Forcada A, Corachán M. Cytomegalovirus and Epstein-Barr Virus Infection as a Cause of Chronic Fatigue Syndrome in Travelers to Tropical Countries. J Travel Med. 1995 Mar 1;2(1):41-44. http://www.ncbi.nlm.nih.gov/pubmed/9815359

 

Epidemiologic study of chronic fatigue in primary care (general practice)

Abstract:

The results of a cross sectional study of fatigue in two large samples of patients attending primary care physicians are reported. The level of complaint of fatigue was higher in the prospective sample, which consisted of patients who had been diagnosed as suffering from a viral infection six months earlier. Duration and frequency of experience of fatigue correlated with severity in both samples. Severity, duration and frequency were continuously distributed in these populations.

Attribution of fatigue in these two samples was mixed: social stresses, current physical illness and psychological problems all being offered as explanations. 11% of the cross sectional sample and 17% of the prospective sample met study operational criteria for a possible chronic fatigue state. These patients were assessed in greater detail. The majority had a diagnosable psychiatric disorder, predominantly depression. Physical illnesses were not adequate to explain these fatigue states.

These studies in primary care do not support a clinical entity of a “chronic fatigue syndrome”. Some patients in primary care settings have complaints of fatigue that are both disabling and long lasting, but they do not form a distinct group although the majority are likely however to be suffering from a concurrent psychiatric disorder. In contrast to similar patients with chronic fatigue syndromes attending hospital clinics, primary care patients with complaints of fatigue are much more varied in their ideas of causation with considerable less evidence of disease conviction.

 

Source: Mann AH, Mc Donald E, Cope H, Pelosi A, David A. Epidemiologic study of chronic fatigue in primary care (general practice). Encephale. 1994 Nov;20 Spec No 3:575-9. [Article in French] http://www.ncbi.nlm.nih.gov/pubmed/7843054

 

Chronic fatigue syndrome: have flawed assumptions been derived from treatment-based studies?

Abstract:

Chronic fatigue syndrome is a disabling disorder that has been studied primarily in clinical settings. In the absence of an adequate epidemiological database, cultural stereotypes have influenced the characterization of chronic fatigue syndrome as “the yuppie flu,” similar to the 19th century characterization of neurasthenia as a disease of the affluent. The limited epidemiological data available and the overall medical-sociological literature call this assumption into question. Only a community “true” prevalence study that is unbiased by help seeking and access to health care can provide an accurate assessment of the risk factors for and the public health ramifications of this disease.

 

Source: Richman JA, Flaherty JA, Rospenda KM. Chronic fatigue syndrome: have flawed assumptions been derived from treatment-based studies? Am J Public Health. 1994 Feb;84(2):282-4. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1615008/

You can read the full article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1615008/pdf/amjph00453-0124.pdf

 

 

An approach to studies of cancer subsequent to clusters of chronic fatigue syndrome: use of data from the Nevada State Cancer Registry

Abstract:

Chronic fatigue syndrome (CFS) has been increasingly associated with immune dysregulation, including depressed natural killer cell activity; this phenomenon is associated with increased susceptibility to cancer. Although anecdotal reports have suggested an association between CFS and cancer, particularly non-Hodgkin’s lymphoma and brain cancer, there has been no a priori justification for evaluating such an association and no consideration of relevant parameters, such as length of latent period vs. tumor type.

We reviewed data from the Nevada State Cancer Registry subsequent to a reported outbreak of a CFS-like illness in Nevada that occurred during 1984-1986. We concentrated on non-Hodgkin’s lymphoma and brain/CNS tumors, with particular emphasis on persons 15-34 and 35-54 years of age.

An upward trend in the incidence of brain/CNS tumors, which could be related to a national upward trend for this disease, was noted. No consistent trends were noted for non-Hodgkin’s lymphoma.

Because of the difficulties inherent in studies of cancer subsequent to various exposures, we evaluated the methodology for determining an association between outbreaks of CFS-like disease and cancer. We propose several approaches that should be considered in future studies for investigation of possible associations between CFS and cancer, including expected latent periods for specific tumors.

 

Source: Levine PH, Atherton M, Fears T, Hoover R. An approach to studies of cancer subsequent to clusters of chronic fatigue syndrome: use of data from the Nevada State Cancer Registry. Clin Infect Dis. 1994 Jan;18 Suppl 1:S49-53. http://www.ncbi.nlm.nih.gov/pubmed/8148453

 

Prevalence of chronic fatigue syndrome-related symptoms among nurses

Abstract:

Chronic Fatigue Syndrome is an illness that is characterized by debilitating fatigue and a group of other related symptoms. Few epidemiological studies have been conducted, and none have focused on a nursing population. The present study is the first to assess the prevalence of Chronic Fatigue Syndrome-related symptoms in a sample of nurses. Demographic characteristics, symptoms, and possible prevalence rates are presented and discussed. When using both narrow and more inclusive criteria to define this symptom complex, higher rates of this disorder were found than in previous epidemiological studies. The implications of these findings are discussed.

 

Source: Jason LA, Taylor SL, Johnson S, Goldston SE, Salina D, Bishop P, Wagner L. Prevalence of chronic fatigue syndrome-related symptoms among nurses. Eval Health Prof. 1993 Dec;16(4):385-99. http://www.ncbi.nlm.nih.gov/pubmed/10130552

 

Report of the working group on the possible relationship between hepatitis B vaccination and the chronic fatigue syndrome

Introduction:

On 2 June, 1992, the Laboratory Centre for Disease Control (LCDC), Health Protection Branch, Department of National Health and Welfare, asked Dr. Gilles Delage to set up an independent working group to evaluate the evidence linking hepatitis B vaccination with the chronic fatigue syndrome (CFS). Dr. Delage agreed to act as the chairman of the group, and experts were recruited in the following fields: clinical investigation of patients with CFS, clinical studies of hepatitis B vaccination in health care workers, epidemiology and study design, public health programs pertaining to hepatitis B vaccination, and immunology of vaccine response. The working group held a 1-day meeting on 2 November, 1992. It reviewed in detail the data collected by LCDC on 30 self-reported cases of CFS (meeting a standard case definition) alleged to be secondary to hepatitis B vaccination. The working group then reviewed data made available by some of its members. After a lengthy discussion, all members of the working group agreed that there is no evidence of a cause-effect relationship between hepatitis B vaccination and CFS. This report outlines the reasons why the group arrived at this conclusion.

You can read the rest of this article here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1485526/pdf/cmaj00271-0068.pdf

 

Source: Report of the working group on the possible relationship between hepatitis B vaccination and the chronic fatigue syndrome. CMAJ. 1993 Aug 1;149(3):314-9. [Article in English, French] http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1485526/

 

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

Abstract:

To determine the medical and psychiatric diagnoses that have an aetiological role in chronic fatigue we conducted a prospective study of 405 (65% women) patients who presented for evaluation with this chief complaint to an academic medical centre.

The average age was 38.1 years and the average duration of fatigue at entry in the study was 6.9 years. All patients were given comprehensive physical and laboratory evaluations and were administered a highly structured psychiatric interview. Psychiatric diagnoses explaining the chronic fatigue were identified in 74% of patients and physical disorders were diagnosed in 7% of patients.

The most common psychiatric conditions in this series were major depression, diagnosed in 58% of patients, panic disorder, diagnosed in 14% of patients, and somatization disorder, diagnosed in 10% of patients. Primary sleep disorders, diagnosed in 2% patients, and chronic infections, confirmed in 1.6% patients, explained the majority of cases whose chronic fatigue was attributed to a physical disorder.

Thirty per cent of patients met the criteria used to define the chronic fatigue syndrome (CFS). Compared with age- and gender-matched control subjects with chronic fatigue, CFS patients had a similarly high prevalence of current psychiatric disorders (78% versus 82%), but were significantly more likely to have somatization disorder (28% versus 5%) and to attribute their illness to a viral infection (70% versus 33%).

We conclude that most patients with a chief complaint of chronic fatigue, including those exhibiting the features of CFS, suffer from standard mood, anxiety and/or somatoform disorders. Careful research is still needed to determine whether CFS is a distinct entity or a variant of these psychiatric illness.

 

Source: Manu P, Lane TJ, Matthews DA. Chronic fatigue and chronic fatigue syndrome: clinical epidemiology and aetiological classification. Ciba Found Symp. 1993;173:23-31; discussion 31-42. http://www.ncbi.nlm.nih.gov/pubmed/8491100

 

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

Abstract:

The US Centers for Disease Control initiated physician-based chronic fatigue syndrome (CFS) surveillance systems in four cities in September 1989 to determine the prevalence, incidence, course and impact of the illness. The participating physicians have referred to our surveillance system 590 patients who were ill during the first two years of surveillance with severe, debilitating, unexplained fatigue for at least the preceding six months.

Referred patients were screened for psychiatric disorders preceding, concurrent with, and subsequent to the onset of their fatigue by specially trained nurses using a modified Diagnostic Interview Schedule. Complete health histories were obtained by interview and review of medical records and a basic panel of standard laboratory diagnostic tests were conducted. Four physicians have independently reviewed the health information of 337 of the patients for classification.

Approximately 26% of patients referred to the surveillance system met the CFS case definition in all regards, 14% lacked one or more of the required eight symptom criteria, 15% were judged to have another possible or known medical illness which could account for the severe fatigue, and the remaining 45% did not meet the case definition because of histories of psychiatric disorders preceding the onset of fatigue.

Minimum prevalence rates for the period 1 September 1989 to 1 September 1991 ranged from 2.0 to 7.3 per 100,000 of the general population across the four study sites and rates based on prorated data ranged from 4.6 to 11.3 per 100,000. More than 80% of the CFS cases were female, most were white, and their average age at onset was approximately 30 years.

 

Source: Gunn WJ, Connell DB, Randall B. Epidemiology of chronic fatigue syndrome: the Centers for Disease Control Study. Ciba Found Symp. 1993;173:83-93; discussion 93-101. http://www.ncbi.nlm.nih.gov/pubmed/8387910