Kim, Cheol Hwan, Shin, Ho Cheol, Won, Chang Won · Journal of Korean medical science · 2005 · DOI
Researchers in Korea asked nearly 1,650 patients visiting primary care clinics about fatigue and checked whether they had chronic fatigue or ME/CFS. They found that about 8% of patients had chronic fatigue, but only 0.6% (less than 1%) had ME/CFS. Most chronic fatigue cases could be explained by physical or psychological causes, while ME/CFS cases had no clear medical explanation.
This is one of few epidemiological studies of ME/CFS in East Asia, providing important geographic diversity to ME/CFS prevalence data which is predominantly from Western populations. The distinction between medically explained chronic fatigue and unexplained CFS helps clarify that most chronic fatigue has identifiable causes, while ME/CFS represents a rarer condition requiring specific diagnostic criteria.
This study does not establish the incidence (new cases) of ME/CFS, only prevalence at a single timepoint. The cross-sectional design cannot determine causation or temporal relationships. The study also does not validate the specific case definitions used, nor does it demonstrate whether findings in Korean primary care generalize to other populations or healthcare settings.
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
Kim, Cheol Hwan, Shin, Ho Cheol, & Won, Chang Won (2005). Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study.. Journal of Korean medical science. https://doi.org/10.3346/jkms.2005.20.4.529
BibTeX
@article{mecfsatlas-kim-2005-prevalence-chronic,
author = {Kim, Cheol Hwan and Shin, Ho Cheol and Won, Chang Won},
title = {Prevalence of chronic fatigue and chronic fatigue syndrome in Korea: community-based primary care study.},
journal = {Journal of Korean medical science},
year = {2005},
doi = {10.3346/jkms.2005.20.4.529},
note = {PubMed: 16100439},
url = {https://www.mecfsatlas.com/evidence/kim-2005-prevalence-chronic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-26. https://www.mecfsatlas.com/evidence/kim-2005-prevalence-chronic
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