Serum Leptin And Interleukin-6 Concentrations And Their Relationship With Bone Quantity In Autoimmune Thyroid Disease

Objective To investigate the change of serum leptin and interleukin-6(IL-6) levels and their effect to bone metabolism in different thyroid function of Autoimmune Thyroid Disease (AITD).Methods 72 patients with AITD were included in the study and divided into hyperthyroidism group(36 Graves' disease patients, 16 males and 20 females) and hypothyroidism group(36 Hashimoto thyroiditis patients, 16 males and 20 females). The normal group include 36 body mass index (BMI)-matched control subjects(16 males and 20 females). Serum leptin and IL-6 levels were measured by enzyme-linked immunosorbent assay (ELISA). Bone mass were measured by UBIS 5000 quantitative ultrasound(QUS). Calcaneal parameters include broadband ultrasound affenuation(BUA), Sound of speed (SOS), Stifmess(STI) and T-score.Results Serum leptin levels(male:2.88 1.53ng/ml; female:7. 63 3.95ng/ml) and Calcaneal parameters value inhyperthyroidism patients were significantly lower than those in the normal group (male:4.53 3.27ng/ml; female: 11. 82 5.94ng/ml). No significantly change of leptin levels and Calcaneal parameters value was found between hypothyroidism (male:3.87 1.59ng/ml; female: 10.62 6.70ng/ml) and normal group. Serum leptin levels were positively correlated with BMI in the hyperthyroidism and hypothyroidism patients as well as normal controls(p<0.05). Serum IL-6 levels(male:163.3 47.8pg/ml; female:292.5 51.6pg/ml) were significantly higher than those in the normal group (male:81.2 29.7pg/ml; female: 128.9 38.6pg/ml). No significantly change of IL-6 levels was found between hypothyroidism (male: 104.9 32.8pg/ml; female: 169.2 56.2pg/ml) and normal group. Serum IL-6 levels were positively correlated with FT3 and FT4 in hyperthyroidism patients(p<0.05). BUA were positively correlated with BMI and leptin in hyperthyroidism and hypothyroidism patients as well as normal controls(p<0.05). BUA were negetively correlated with IL-6 and FT4 in hyperthyroidism patients.(p<0.05). Multivariate regession analysis indicated that BUA were still negetivelycorrelated with IL-6 and positively correlated with BMI and leptin in hyperthyroidism patients(p<0.0001).Conclusion The above results suggest that serum leptin and IL-6 levels change in Graves' hyperthyroidism patients and they are nearly associated with the bone mass change with hyperthyroidism. The increase of leptin and decrease of IL-6 level might induce the bone loss in hyperthyroidism. Leptin and IL-6 may be the predictors for severity of hyperthyroidism and its bone loss.