Leptin levels in Arabs with primary hyperthyroidism

Background: The aim of this report was to study leptin status in hyper-thyr oid men and women (prior to and after medical treatment) and in matched con trols in Arabs. Subjects and Methods: Twenty-nine hyperthyroid patients (19 women and 10 me n) and 32 controls (20 women and 12 men) matched for age, ethnic status and body mass index (BMI) were studied. The patients were studied at the time of diagnosis and six month?; after antithyroid treatment with carbimazole-t itrating dose, which rendered them euthyroid. On each study occasion, the s ubject's fasting blood was collected for the measurement of leptin, glucose , insulin and C-peptide, Results: Fasting leptin level was significantly lower in women with hyperth yroidism at baseline (mean+/-SEM, 15.8+/-2.9 mug/L, P=0.01), and after six months of antithyroid treatment (13.4+/-1.7 mug/L, P=0.004) than in control women (25.6+/-2.7 mug/L), but the difference was not significant in the me n. Women in each group had significantly higher leptin concentrations than men (patients: 15.8+/-2.9 vs. 4.9+/-0.9 mug/L, P=0.009; controls: 25.6+/-2. 7 vs. 7.9+/-1.4 mug/L, P=0.0005). The differences in women's leptin remaine d significant even when expressed in relation to BMI. Baseline fasting gluc ose (P=0.01), insulin (P=0.007), and C-peptide (P=0.02) were significantly higher in the patients than controls. After six months of antithyroid thera py, fasting glucose, insulin and C-peptide levels were similar in the patie nts and controls. Within the patients, baseline leptin concentrations corre lated positively with BMI (rho=0.65, P=0.02) and negatively with free T3 (r ho=-0.62, P=0.03). It neither demonstrated an association with baseline nor with six-month values of fasting glucose, insulin and C-peptide. Conclusion: Leptin concentration is decreased in Arab women with hyperthyro idism. Six months of antithyroid therapy is not associated with alterations in leptin levels.