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Prolonged fatigue in Ukraine and the United States: Prevalence and risk factors.
Friedberg, Fred, Tintle, Nathan, Clark, Jake et al. · Fatigue : biomedicine, health & behavior · 2015 · DOI
Quick Summary
This study compared how common prolonged, disabling fatigue is in Ukraine versus the United States by surveying thousands of people in both countries. Researchers found that prolonged fatigue was more common in Ukraine (5.2%) than in the U.S. (3.7%), and identified different risk factors in each country—such as socioeconomic status, mood disorders, and various health conditions. Importantly, about one-fifth of people with prolonged fatigue had no other diagnosed medical or mental health condition.
Why It Matters
This study provides international epidemiological data on prolonged fatigue prevalence and identifies that a significant proportion of people with disabling fatigue have no other recognized medical or psychiatric diagnosis—suggesting fatigue can be a primary condition worthy of clinical attention. Understanding varied risk factors across populations helps researchers identify whether fatigue pathophysiology differs by geography or whether environmental and socioeconomic factors modulate disease presentation and recognition.
Observed Findings
Lifetime prevalence of prolonged fatigue was 5.2% in Ukraine versus 3.7% in the U.S.
Approximately 20% of individuals with prolonged fatigue had no co-occurring medical or DSM-IV psychiatric condition in both countries.
Female gender, unemployment, and prior marriage were associated with fatigue in both countries.
Mood and anxiety disorders in both early-life and adulthood were significantly associated with prolonged fatigue in both countries.
Fatigue prevalence increased with age in Ukraine but decreased after age 70 in the U.S.
Inferred Conclusions
Prolonged fatigue can occur as a primary condition independent of other diagnosed medical or psychiatric disorders.
Risk factors for prolonged fatigue are partially shared across populations but also include country-specific sociodemographic and health-related factors.
Environmental stressors and resource limitations may contribute to higher fatigue prevalence in Ukraine.
Early-life mood/anxiety disorders and adult episodes of these conditions are important correlates of prolonged fatigue in both countries.
Remaining Questions
Does the higher prevalence of prolonged fatigue in Ukraine reflect true differences in disease epidemiology, or differences in help-seeking behavior and diagnostic recognition?
What This Study Does Not Prove
This study does not prove that any identified risk factor *causes* prolonged fatigue—it only shows associations. The cross-sectional design cannot establish temporal relationships between risk factors and fatigue onset. Additionally, the study uses neurasthenia (ICD-10) rather than ME/CFS diagnostic criteria, so findings may not directly apply to ME/CFS specifically.
Tags
Symptom:Fatigue
Method Flag:PEM Not DefinedWeak Case DefinitionMixed Cohort
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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What distinguishes the 20% of people with prolonged fatigue who have no other medical or psychiatric condition—do they represent a distinct pathophysiological phenotype?
Why does fatigue prevalence decrease after age 70 in the U.S. but continue to increase in Ukraine, and what role do cohort effects versus true age effects play?
How do the risk factors identified in this neurasthenia study compare to those in ME/CFS populations, and are these the same condition?