Weir, Peter T, Harlan, Gregory A, Nkoy, Flo L et al. · Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases · 2006 · DOI
This study looked at how often fibromyalgia is diagnosed in a large group of insured people over a 6-year period. The researchers found that fibromyalgia is diagnosed more often in women than men, though not as dramatically as previous studies suggested. People with fibromyalgia were much more likely to also have other conditions like depression, anxiety, headaches, irritable bowel syndrome, chronic fatigue syndrome, lupus, and rheumatoid arthritis.
This study is significant for ME/CFS patients because it establishes strong epidemiological associations between fibromyalgia and chronic fatigue syndrome as comorbid conditions, suggesting shared pathophysiological mechanisms or overlapping disease processes. Understanding the incidence and comorbidity patterns of fibromyalgia helps clarify the broader landscape of chronic conditions that frequently co-occur with ME/CFS, which may inform diagnostic and treatment approaches.
This study does not establish causality between fibromyalgia and its associated comorbidities—it only documents that they occur together more frequently than by chance. It cannot explain whether fibromyalgia causes these conditions, these conditions cause fibromyalgia, or whether shared underlying biological mechanisms link them. The study also does not validate diagnostic accuracy or assess whether coding errors affected the incidence estimates.
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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