Endocrine Abstracts

The aim of this study was to assess the physical well-being among women with thyrotoxicosis. It was important to investigate the relationship between thyrotoxicosis and muscle quantity and quality as being components of sarcopenia.

Methods

36 women over 40 years of age with thyrotoxicosis took part in this cross-sectional study. After excluding factors affecting physical performance and body composition 13 women remained (mean age 64 ± 9.38 years). Anthropometric parameters were measured. Grip strength was used to assess muscle strength. As recommended by The European Working Group on Sarcopenia in Older People 2 (EWGSOP2), appendicular skeletal muscle mass (ASM), adjusted for body size (ASM/height²) was used to asses muscle quantity. Physical performance was measured by gait speed test. We divided women in two groups: group A- patients with newly diagnosed thyrotoxicosis prior to treatment and group B- patients who had already started treatment. Group A consisted of 46.2% of the participants (6 women) and group B- 53.8% (7 women).

Results

We found no association between thyroid hormone levels and grip strength, gait speed or ASM/height². Only the anti-thyroid peroxidase antibodies (TPO-Ab) correlated negatively with borderline significance with gait speed (r –0.546; р 0.054). A statistical significant positive correlation was established also between TPO-Ab and ASM/height² (r 0, 697; p 0.008). Although insignificant, a tendency for decreasing values of muscle strength and mass in group A compared to group B was observed. Probable sarcopenia is identified by low muscle strength and while it didn’t reach the cut-off point for sarcopenia, it was lower in group A (23.5 ± 10.291 kg). It tended to increase and reached normal levels in group B (31.86 ±10.107 kg). The same tendency was observed for muscle mass and gait speed - they were lower in group A and increased in group B. Only 2 of the patients in group A had grip strength less than 16 kg, and there was 1 patient with borderline value (19 kg). All the three of them were diagnosed with severe sarcopenia by additional documentation of low muscle quantity and low physical performance. Thus the frequency of sarcopenia was 50% in newly diagnosed patients with thyrotoxicosis. None of the women in group B met the criteria for sarcopenia.

Conclusions

Despite the small number of women in this study, we can conclude that untreated thyrotoxicosis is a risk factor for decreased muscle strength, muscle quantity and physical performance and thus could cause secondary sarcopenia.