Abstract
Background and aims:
Evidence exists that autoimmune thyroiditis is present in a high percentage of fibromyalgia
(FM) and associated with the presence of typical symptoms of FM. However, the role
of thyroperoxidase antibody (TPO Ab) in the manifestation of FM is still unclear.
The goal of this study was to investigate the prevalence of positive TPO Ab in euthyroid
FM patients, and whether TPO Ab positivity is associated with the clinical manifestations
in euthyroid FM patients.
Subjects and Methods:
Thyroid assessment was done by free T4, TSH and TPO Ab. The clinical parameters including
Fibromyalgia Impact questionnaire (FIQ), pain visual analogical scale (VAS) and tender
point counts were evaluated in euthyroid primary FM patients, not associated with
autoimmune rheumatic disease. The immunologic tests including rheumatoid factor and
antinuclear antibody were measured. We compared the prevalence of positive TPO Ab
between FM patients, and healthy control. We also compared clinical and laboratory
parameter in FM patients according to the presence of TPO Ab.
Results:
149 patients of FM, 68 healthy controls were recruited. FM patients showed higher
prevalence of positive TPO Ab than healthy controls (28 out of 149 patients, 19%;
5 out of 68 healthy controls, 7%; P=0.04). There was no difference of clinical and
laboratory parameters in FM patients between 2 groups subdivided by the presence of
TPO Ab.
Conclusion:
In our study, euthyroid FM patients showed significantly higher prevalence of positive
TPO Ab, as compared to age and sex matched healthy control. However, TPO Ab positivity
was relatively low and not associated with the clinical manifestations in euthyroid
FM patients. This finding support thyroid autoimmunity may influence the development
of FM, but the evidence which support that FM is related to autoimmune etiology is
not clear, and FM severity may not be affected by the presence of thyroid autoantibody.
Key words thyroid - autoimmunity - Fibromyalgia