High rates of autoimmune and endocrine disorders, fibromyalgia, chronic fatigue syndrome and atopic diseases among women with endometriosis: a survey analysis. — CFSMEATLAS
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High rates of autoimmune and endocrine disorders, fibromyalgia, chronic fatigue syndrome and atopic diseases among women with endometriosis: a survey analysis.
Sinaii, N, Cleary, S D, Ballweg, M L et al. · Human reproduction (Oxford, England) · 2002 · DOI
Quick Summary
This study found that women with endometriosis—a painful condition where tissue grows outside the uterus—have much higher rates of ME/CFS, fibromyalgia, and autoimmune diseases compared to the general population. Researchers surveyed nearly 3,700 women with endometriosis and compared their health conditions to published data about women without endometriosis. Women with endometriosis were 150 times more likely to have ME/CFS and nearly twice as likely to have fibromyalgia.
Why It Matters
This study demonstrates a significant epidemiological association between endometriosis and ME/CFS, suggesting shared underlying immune dysregulation mechanisms. For ME/CFS patients and researchers, understanding the high co-occurrence of these conditions may provide clues about common pathophysiological pathways involving autoimmune activation, endothelial dysfunction, and immune dysregulation that warrant further investigation.
Observed Findings
Women with endometriosis had chronic fatigue syndrome rates of 4.6% compared to 0.03% in the general population—a 150-fold difference
Fibromyalgia prevalence was 5.9% in endometriosis patients versus 3.4% in the general population
Autoimmune conditions were significantly elevated: hypothyroidism (9.6% vs 1.5%), systemic lupus erythematosus (0.8% vs 0.04%), and Sjögren's syndrome (0.6% vs 0.03%)
Allergies and asthma were particularly common in endometriosis patients with fibromyalgia or CFS (88% and 25% respectively) compared to 18% and 5% in the general population
99% of survey respondents reported pain, and 41% reported infertility
Inferred Conclusions
Hypothyroidism, fibromyalgia, chronic fatigue syndrome, and autoimmune diseases are significantly more common in women with endometriosis than in the general female population, suggesting potential shared pathophysiological mechanisms
The particularly high prevalence of allergies and asthma in endometriosis patients with fibromyalgia or CFS suggests these comorbid conditions may represent a distinct phenotype of immune dysregulation
Endometriosis may be associated with broader immune system dysfunction affecting multiple organ systems and disease susceptibilities
Remaining Questions
Does endometriosis cause ME/CFS, or do both conditions share a common underlying immune dysregulation mechanism?
What This Study Does Not Prove
This study does not establish causation—it cannot determine whether endometriosis causes ME/CFS, whether ME/CFS causes endometriosis, or whether both conditions share a common underlying cause. The cross-sectional design and reliance on self-reported data and historical comparisons (rather than matched concurrent controls) limit causal inference. The study also does not prove that the elevated rates reflect true biological associations versus potential diagnostic bias or shared symptom reporting patterns.
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 →
What specific immunological abnormalities are shared between endometriosis, ME/CFS, and fibromyalgia?
Do women with endometriosis and comorbid ME/CFS have different clinical presentations, disease severity, or prognosis compared to those with each condition alone?
Can prospective studies confirm these associations and explore temporal relationships between disease onset?