Endocrine Abstracts

Severe thyroid disorder are associated with important metabolic changes. After restoration of euthyroidism, as a result of proper treatment, usually body metabolism also normalizes. Up to date, there are conflicting reports about the changes in body composition of patients during treatment of severe hyperthyroidism and hypothyroidism. The aim of this study was to evaluate the body composition and glucose level changes in subjects affected by Graves disease and autoimmune thyroid disease before the treatment and after achieving euthyroidism. The study group consisted of 33 patients affected by hyperthyroidism diagnosed with Graves’ disease, and 20 patients suffering from hypothyroidism due to autoimmune thyroid disease. In all patients body composition with the use of bioimpendace method, glucose and thyroid-related hormones levels were evaluated at the moment of diagnosis and after restoration of euthyroidism. The mean observation time was 10.5 months for hypothyroid group and 7 months for hyperthyroid group. After restoration of euthyroidism hypothyroid group presented decreased body weight, body mass index, fat-free mass, muscle mass. There was no changes in fat mass and glucose concentration. On the other hand, in the hyperthyroid group achieving euthyroidism was associated with increase in body weight, BMI, fat mass, fat percentage, as well as decrease in glucose concentration. There was no significant difference in muscle mass. The changes in body weight, BMI and fat mass correlated positively with TSH changes and negatively with fT3 and fT4 changes. Muscle mass changes correlated positively with TSH changes and negatively with fT3 changes. To conclude, while increased body mass after the treatment of hyperthyroidism was a result of predominantly fat accumulation, hypothyroid patients lost their body weight mainly due to decreased muscle mass. However, both hyperthyroidism and hypothyroidism causes fat as well as muscle tissue changes.