Ranjith, G · Occupational medicine (Oxford, England) · 2005 · DOI
This review examined research on how common ME/CFS is in different populations and what factors might be linked to it. While fatigue itself is very common, ME/CFS is actually quite rare. Interestingly, some patterns seen in specialist clinics (like who gets sick) don't always match what researchers find when they study the general population.
Understanding the true epidemiology of ME/CFS—its actual frequency, who is affected, and what patterns exist in the general population versus specialist settings—is essential for proper resource allocation, reducing diagnostic delays, and directing research efforts toward genuine risk factors rather than biases introduced by healthcare-seeking behavior in clinic samples.
This review does not establish causation for any identified associations, nor does it prove that factors observed in specialist clinics actually drive ME/CFS development. The heterogeneity in case definitions and study methodologies means findings cannot be simply combined to determine definitive prevalence or incidence rates. The review also cannot determine whether psychiatric comorbidity causes, results from, or is coincidental to ME/CFS.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Ranjith, G (2005). Epidemiology of chronic fatigue syndrome.. Occupational medicine (Oxford, England). https://doi.org/10.1093/occmed/kqi012
BibTeX
@article{mecfsatlas-ranjith-2005-epidemiology-chronic,
author = {Ranjith, G},
title = {Epidemiology of chronic fatigue syndrome.},
journal = {Occupational medicine (Oxford, England)},
year = {2005},
doi = {10.1093/occmed/kqi012},
note = {PubMed: 15699086},
url = {https://www.mecfsatlas.com/evidence/ranjith-2005-epidemiology-chronic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/ranjith-2005-epidemiology-chronic
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