Reputedly, thyroid hormones make thinner and change the body composition. The aim of this randomized and prospective study was the assessment of the effect of levothyroxine suppressive therapy on body composition in women with benign thyroid nodule.
Method: Thirty seven euthyroid and non obese women (1860 years old) with benign thyroid nodule (fine needle cytology and calcitonin measurement) were randomized into 2 equal groups. The first group received gradually 1.7 μg/kg of levothyroxine during one year and the second (control group) was not treated. The body composition was evaluated by bioelectric impedance and biphotonic absorptiometry, body density by plethysmography, energy expenditure by indirect calorimetry and muscular function was evaluated by effort test.
Results: At the end of the study, TSH was lower in the treated group than in the no treated group (0.58±0.30 mUI/l and 1.21±0.50 N: 0.353.5). The body composition didnt change. There was no difference in weight (62+/9.51 vs 61.74±6.98 kg, P>0.5), nor body density (1.04±0.019 vs 1.04±0.02 kg/l, P>0.5). The energy expenditure wasnt different between the 2 groups during the study (1376 kCal/j in the treated group vs 1374 kCal/j in the no treated group, P>0.5), circulating leptine level was the same in the 2 groups too (12.7 vs 12.4 ng/ml) and the muscular function was not altered by levothyroxine therapy (equal decrease oxygen consumption in the 2 groups).
Conclusion: There was no modification of body composition, muscular function and energy expenditure in women received levothyroxine suppressive therapy for thyroid benign nodule, during one year. The treatment doesnt appear deleterious.
01 - 05 Apr 2006
European Society of Endocrinology