Plasma visfatin concentrations increase in both hyper and hypothyroid subjects after normalization of thyroid function and are not related to insulin resistance, anthropometric or inflammatory parameters

Abstract

Objective The objective of this study was to evaluate plasma visfatin levels in thyroid dysfunction and its relationship with inflammatory, anthropometric and insulin resistance parameters. Design and patients Twenty-four hyperthyroid and 27 hypothyroid patients were studied before and after treatment. Forty-five euthyroid subjects were used as control group. Measurements Fasting plasma visfatin, IL-6, C reactive protein, adiponectin, thyroid hormones, waist-to-hip ratio, BMI, percentage of body fat and homeostasis model insulin resistance index (HOMA-IR) were measured. Results Hyperthyroid patients showed increased insulin resistance, IL-6 and visfatin levels compared with controls (3·21 ± 3·0 vs. 1·67 ± 0·75, P = 0·022; 3·35 ± 0·41 vs. 2·10 ± 0·25 pg/ml, P = 0·016; and 37·4 ± 5·81 vs. 23·79 ± 4·2 ng/ml, P = 0·061 respectively). After normalization of thyroid function, IL-6 levels and HOMA-IR decreased (2·35 ± 0·37 vs. 2·10 ± 0·25 pg/ml, P = 0·045 and 3·21 ± 0·60 vs. 2·28 ± 0·38, P = 0·032 respectively), while body weight, adiposity and visfatin levels increased (26·1 ± 1·2 vs. 26·7 ± 1·2 kg/m 2, P = 0·049; 30·9 ± 1·6 vs. 32·2 ± 1·6%, P = 0·007; and 37·4 ± 5·81 vs. 63·13 ± 8·72 ng/ml, P = 0·047 respectively). C reactive protein and adiponectin levels were similar to those of the control group. Hypothyroid patients showed high visfatin levels (40·59 ± 3·07 vs. 29·34 ± 4·9 ng/ml, P = 0·049) that increased after treatment (81·4 ± 9·2 ng/ml, P = 0·001) without changes in anthropometric or insulin resistance parameters. C reactive protein, IL-6 and adiponectin levels were similar to those of the control group. No correlations between visfatin and any analysed parameter were found in either hyper- or hypothyroidism. Conclusion Visfatin exhibits a marked increase after normalization of thyroid function in both hyper and hypothyroid patients. We suggest that visfatin may play a role in the hormone stabilization process independent of anthropometric, inflammatory or insulin resistance variables. © 2009 Blackwell Publishing Ltd.