Eccles, Jessica A, Thompson, Beth, Themelis, Kristy et al. · Clinical medicine (London, England) · 2021 · DOI
This study looked at whether joint hypermobility (unusual flexibility and loose joints) is connected to fibromyalgia and ME/CFS. Researchers found that most patients with these conditions also had signs of hypermobility, and that higher hypermobility scores matched with worse symptoms. The results suggest that hypermobility is often missed in diagnosis, even though it significantly affects how sick people feel.
This research highlights that connective tissue disorders are frequently overlooked in ME/CFS patients despite having significant clinical impact. Recognizing hypermobility as a common co-occurring condition could improve diagnosis accuracy and guide targeted treatments, potentially improving quality of life for many ME/CFS patients who remain undiagnosed.
This study does not prove that hypermobility causes ME/CFS or fibromyalgia—it only shows they occur together. The observational design means we cannot determine the direction of causality or whether hypermobility is a primary driver of symptoms versus a coincidental feature. The study's small size and lack of age/sex-matched controls also limit how broadly these findings apply to the full ME/CFS population.
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
Eccles, Jessica A, Thompson, Beth, Themelis, Kristy, Amato, Marisa L, Stocks, Robyn, Pound, Amy, et al. (2021). Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study.. Clinical medicine (London, England). https://doi.org/10.7861/clinmed.2020-0743
BibTeX
@article{mecfsatlas-eccles-2021-beyond-bones,
author = {Eccles, Jessica A and Thompson, Beth and Themelis, Kristy and Amato, Marisa L and Stocks, Robyn and Pound, Amy and Jones, Anna-Marie and Cipinova, Zdenka and Shah-Goodwin, Lorraine and Timeyin, Jean and Thompson, Charlotte R and Batty, Thomas and Harrison, Neil A and Critchley, Hugo D and Davies, Kevin A},
title = {Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study.},
journal = {Clinical medicine (London, England)},
year = {2021},
doi = {10.7861/clinmed.2020-0743},
note = {PubMed: 33479068},
url = {https://www.mecfsatlas.com/evidence/eccles-2021-beyond-bones},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/eccles-2021-beyond-bones
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