Endocrine Abstracts

Thyroid hormones (TH) are key regulators of basal metabolic rate and body weight. They increase resting energy expenditure by increased synthesis of uncoupling protein-1 (UCP-1) in brown adipocytes which stimulates energy dissipation as a heat. TH also increase appetite by central adrenergic stimulation. Body weight change is a key symptom of thyroid dysfunction especially the weight gain observed in patients treated for hyperthyroidism AIM: To compare the influence of different methods of Graves disease treatment on body composition and insulin sensitivity.

Methods

Pairwise comparison of 50 patients with Graves disease treated with radioiodine or antithyroid drugs (ATDs) in hyperthyroid state and three months after euthyroidism was established. Body composition changes were determined with dual energy X-ray absorptiometry (DXA). Glucose and insulin serum concentration were measured and QUICKI index calculated. Body composition analysis was performed separately in women ( n = 43 ) and men ( n = 7 ).

Results

Independently of treatment method there was significant increase in body fat ( BF) and lean tissue mass (LTM ), with BF rise dominating in men whereas LTM increase being more pronounced in women. BF increased by 2.43 ( 0.58;3.0 ) kg in women and 4.18 ( 0.25; 8.09 ) kg in men, whereas LTM increased by 3.84 ( 1.75 ; 4.35) kg in women and 0.77 (0.2–6.10) kg in men. There was no difference in BF, trunk body fat, legs body fat and LTM in women treated with radioiodine (n = 33) as compared to ATDs treated women (n = 10) ( 2.57 vs 1.3 kg, P = 0.711; 1.37 vs 0.88 kg, P = 0.702; 0.68 vs 0.72 kg, P = 0.596; 3.68 kg vs 2.13 kg, P = 0.910 respectively) and in a small sample of men (n = 7). In radioiodine treated group insulin sensitivity improvement was observed. There was decrease in serum insulin and glucose levels {7.40 (5.28; 9.55) vs 5.05 (3.70; 6.4) uIU\ml, P = 0.018 ; 95.18 (91.77; 101.32) vs 92.06 (87.89; 96.47) mg%/ P = 0.023 respectively} and increase in QUICKI index ( 0.36 ± 0.04 vs 0.38 ± 0.04 ; P = 0.014). Insulin decrease was greater in radioiodine treated as compared to ATDs treated patients {-2.35 (-3.85; 0.35) vs 0.12 (-1.89; 2.14) uIU\ml, P = 0.056} however glucose, QUICKI and HOMA didn’t differ significantly between groups.

Conclusions

There was no difference in BF and LTM changes between radioiodine and ATDs treated patients. In women body weight increase was predominately caused by LTM rise. Despite of body weight gain there was improvement of insulin sensitivity after radioiodine treatment.