Tag: methodology

Chronic fatigue syndrome. …and study them separately

Comment on: Chronic fatigue syndrome: prevalence and outcome. [BMJ. 1994]

 

Editor,-The struggle over myalgic encephalomyelitis and the chronic fatigue syndrome is not, as S M Lawrie and A J Pelosi suggest, whether they are physical or mental illnesses. Both sides in this debate accept that most illnesses combine organic and psychological factors. The struggle is about methodology and definition and, in particular, how different methodologies and definitions inevitably lead to different findings on the degree to which depression is a perpetuating agent in these conditions.

One side favours studying the chronic fatigue syndrome as a single entity, arguing that there is insufficient knowledge at present to differentiate between different chronic fatigue syndromes. This side prefers Sharpe et al’s broad definition of the syndrome, which includes depressive illness, anxiety disorders, and the hyperventilation syndrome.2 Unsurprisingly, studies that use these criteria find higher levels of depression ) or “psychosocial disorders”-yet another woolly term).

The other side argues that there is sufficient knowledge to distinguish specific chronic fatigue syndromes, particularly the much studied myalgic encephalomyelitis, and that it must be better science in these cases to study such syndromes in their own right. Furthermore, it argues that the study groups used in research based on broadbrush criteria will have been so aetiologically heterogeneous as to invalidate the findings. This side, which includes the national patient organisations, equates myalgic encephalomyelitis with Holmes et als tighter definition of the chronic fatigue syndrome, which focuses more on organic symptoms and, again unsurprisingly, finds lower levels of depression similar to those found in patients with cancer and multiple sclerosis-that is, the levels that might be predicted in any chronic illness.3

You can read the rest of this comment here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540172/pdf/bmj00440-0054a.pdf

 

Source: Anderson N. Chronic fatigue syndrome. …and study them separately. BMJ. 1994 May 14;308(6939):1298. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2540172/

 

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