Líndal, Eiríkur, Stefánsson, Jón G, Bergmann, Sverrir · Nordic journal of psychiatry · 2002 · DOI
This study asked over 2,500 Icelanders about symptoms of chronic fatigue syndrome (CFS) to find out how many people have it. Different diagnosis criteria gave very different results—ranging from 0% to 4.9%—showing that how doctors define CFS matters a lot. The study found that women made up most of the people with CFS, and there were some interesting differences between men and women in their symptoms.
This is the first prevalence study of CFS in Iceland or Scandinavia, providing epidemiological data for an understudied region. The stark variation in prevalence across diagnostic criteria highlights the critical importance of case definition standardization in CFS research and the potential for misclassification. Understanding gender differences in symptom presentation may improve diagnosis and guide patient-centered research.
This study does not establish causation regarding stress and CFS onset—participants' beliefs about stress-related onset are subjective reports, not validated evidence of etiology. The cross-sectional design cannot determine whether observed lifestyle factors (e.g., long work hours, unskilled employment) are risk factors or consequences of illness. The wide range of prevalence estimates also reflects limitations in case definition rather than true disease variation.
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
Líndal, Eiríkur, Stefánsson, Jón G, & Bergmann, Sverrir (2002). The prevalence of chronic fatigue syndrome in Iceland - a national comparison by gender drawing on four different criteria.. Nordic journal of psychiatry. https://doi.org/10.1080/08039480260242769
BibTeX
@article{mecfsatlas-lndal-2002-prevalence-chronic,
author = {Líndal, Eiríkur and Stefánsson, Jón G and Bergmann, Sverrir},
title = {The prevalence of chronic fatigue syndrome in Iceland - a national comparison by gender drawing on four different criteria.},
journal = {Nordic journal of psychiatry},
year = {2002},
doi = {10.1080/08039480260242769},
note = {PubMed: 12470318},
url = {https://www.mecfsatlas.com/evidence/lndal-2002-prevalence-chronic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/lndal-2002-prevalence-chronic
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