Lim, Eun-Jin, Son, Chang-Gue · Journal of clinical medicine · 2021 · DOI
This study looked at how common ME/CFS is in Korea and Japan by reviewing eight existing studies. Researchers found that about 0.76-0.77% of people in these countries have ME/CFS—meaning roughly 1 in 130 people. Women were affected about twice as often as men in Korea, though this difference was smaller in Japan.
This is one of the first systematic reviews of ME/CFS prevalence in Asian populations, filling an important gap in our understanding of how common this disease is globally. The variation in gender differences between countries raises questions about whether cultural, genetic, or diagnostic factors influence who develops and is diagnosed with ME/CFS.
This study does not explain why ME/CFS occurs or identify causes of the disease. It also cannot determine whether the gender differences reflect true biological differences in disease susceptibility or differences in how men and women are diagnosed and reported across countries. The prevalence estimates have wide confidence intervals, indicating substantial uncertainty.
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
Lim, Eun-Jin & Son, Chang-Gue (2021). Prevalence of Chronic Fatigue Syndrome (CFS) in Korea and Japan: A Meta-Analysis.. Journal of clinical medicine. https://doi.org/10.3390/jcm10153204
BibTeX
@article{mecfsatlas-lim-2021-prevalence-chronic,
author = {Lim, Eun-Jin and Son, Chang-Gue},
title = {Prevalence of Chronic Fatigue Syndrome (CFS) in Korea and Japan: A Meta-Analysis.},
journal = {Journal of clinical medicine},
year = {2021},
doi = {10.3390/jcm10153204},
note = {PubMed: 34361987},
url = {https://www.mecfsatlas.com/evidence/lim-2021-prevalence-chronic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/lim-2021-prevalence-chronic
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