Background Muscle symptoms are frequent in thyroid diseases, and it has been recognized that there are significant similarities between the clinical findings in FM and symptoms of thyroid dysfunction. Some recent reports have found clinical and biochemical features of muscle dysfunction even in subclinical hypothyroidism. Another study reported that FM patients had some problems in the production or utilization of thyroid hormones, and there was an association between thyroid autoimmunity and FM.
Objectives we performed this study to evaluate the effect of thyroid hormone variation and in particular, the effect of ‘high-normal’ TSH with positive antithyroid antibodies on endothelial function in euthyroid FM patients, using pulse wave velocity(PWV), which assess endothelial function by measuring the status of large and small arteries in the lower extremity.
Methods This study included 155 postmenopausal female FM patients (51.5±8.9 years) without any known cardiovascular diseases within a normal reference range of thyroid-stimulating hormone (TSH) levels (0.4–4.5mIU/ml). The clinical parameters including Fibromyalgia Impact questionnaire (FIQ), pain visual analogical scale (VAS) and tender point counts and immunologic tests including rheumatoid factor and antinuclear antibody were measured. Vascular function was assessed by brachial-ankle pulse wave velocity (baPWV), augmentation index and flow-mediated dilation (FMD). We evaluated the associations between arterial markers and serum TSH, free thyroxin, as well as serum thyroidperoxidase autoantibody.
Results The baPWV values of positive TPO Ab and those with negative TPO Ab (1632.1±385.2 cm/sec vs. 1323.2±210.7 cm/sec, P=0.015) were significantly different. Mean levels of PWV and FMD did not increase linearly across increasing TSH quartiles. No associations were found between the remaining markers and levels of thyroid hormones, whereas thyroid antibodies were significantly associated with baPWV (r=0.337, p=0.007). Linear regression analysis revealed that the only significant predictors of baPWV were age, FIQ and presence of TPO Ab. No significant association was found between FMD and positive anti-TPO antibodies.
Conclusions FM women with positive TPO antibodies have increased arterial stiffness compared to women with negative TPO antibodies. The combined thyroid autoimmunity in FM patients may need re-evaluation with respect to the effects on the vasculature.
Disclosure of Interest None Declared
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