Endocrine Abstracts

Introduction: Grip strength is a valuable biomarker of an individual’s biological age. Weak grip strength is a key component of sarcopenia and frailty and is associated with subsequent poor health, disability and mortality. Skeletal muscle is one of the major target organs of thyroid hormones. Hyperthyroidism may affect skeletal muscles qualitatively and quantitatively, to the extent of developing muscle weakness and myopathy. There are few studies investigating grip strength in patients with newly diagnosed hyperthyroidism.

Aim: The aim of this study is to assess the association of hyperthyroidism with grip strength. To achieve our goal, we set the following tasks: to compare grip strength between healthy females and women with newly diagnosed hyperthyroidism and to look for correlation between anthropometric or thyroid parameters and grip strength.

Materials and Methods: We evaluated 90 women over the age of 18, divided into 2 groups: group A (n =45) women with newly diagnosed untreated hyperthyroidism (autoimmune thyroid disease or toxic nodular goiter) and group B (n =45) - healthy females of the same age. We evaluated anthropometric parameters, laboratory tests of TSH, free T3 (FT3), free T4 ( FT4), TPO-Ab and TRAb. Grip strength was analyzed using a hand-held dynamometer. Statistical analysis was performed by SPSS version 18 for Windows. We used statistical grouping of the data, descriptive methods, Pearson correlation and T-test for statistical hypotheses.

Results: Grip strength testing showed approximately twice as much weakness in hyperthyroid women (16.67 ± 5.96 kg) compared to euthyroid ones (33.82 ± 10.22 kg). There were significant positive correlations between handgrip strength and weight, waist and hip circumferences and BMI. With the reduction of TSH from normal to hyperthyroid values, the grip strength also decreased (p 0,001; r 0,658). As expected, the same, but negative trend between FT3 and grip strength was observed (p 0,013; r -0,274). With the immunological evolution of the disease from euthyroidism to autoimmune hyperthyroidism, expressed by the rise of TPO-Ab and TRAb, a significant reduction of grip strength was observed. In conclusion, hyperthyroidism may affect the skeletal muscles qualitatively and quantitatively. Grip strength in hyperthyroid women is significantly affected by the autoimmune thyroid disorder.