Evengård, Birgitta, Jacks, Andreas, Pedersen, Nancy L et al. · Psychological medicine · 2005 · DOI
This Swedish study contacted over 31,000 people and found that about 2.4% had symptoms matching chronic fatigue syndrome. Women were nearly four times more likely to have these symptoms than men. The researchers were surprised to find that ME/CFS may be more common than doctors previously thought.
This is one of the largest population-based epidemiological studies of ME/CFS conducted in a well-characterized cohort, providing robust prevalence estimates and revealing the striking female predominance of the illness. The findings challenge assumptions about occupational risk and suggest ME/CFS may affect a larger proportion of the population than previously recognized, with important implications for healthcare planning and research priorities.
This study does not identify causes of ME/CFS or explain why women are disproportionately affected; it only documents the association. The cross-sectional design cannot establish temporal relationships or causation. Additionally, reliance on symptom screening and medical record review may miss or misclassify cases depending on how closely the refined definition matched the true clinical entity.
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 →
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