Adiponectin levels and cardiovascular risk factors in hypothyroidism and hyperthyroidism.

OBJECTIVE: Adiponectin, an adipose tissue-derived hormone, has been reported to have anti-inflammatory and anti-atherogenic effects. The physiological effect of adiponectin on the metabolic changes and its relation with cardiovascular risk factors in thyroid dysfunction states is still not clear. The aim of the study was to evaluate plasma adiponectin level and its relation to cardiovascular risk factors in patients with thyroid dysfunction.

PATIENTS AND MEASUREMENTS: Sixty-seven patients with hypothyroidism, 56 patients with hyperthyroidism and 52 age- and sex-matched euthyroid subjects were enrolled in the study. Adiponectin, C-reactive protein (CRP), homocysteine (Hcy), lipid parameters, Lipoprotein(a) [Lp (a)], Apolipoprotein (Apo) A, Apo B and fibrinogen levels were measured in all subjects. Insulin sensitivity was determined using the Homeostasis Model Assessment (HOMA-IR).

RESULTS: Circulating adiponectin levels were not different between the groups (16.2 +/- 5.0, 15.1 +/- 3.7, 15.9 +/- 4.8 ng/ml; hypothyroid, hyperthyroid, euthyroid group, respectively). Plasma adiponectin levels correlated negatively with body mass index (BMI) and HOMA-IR index and positively with high-density lipoprotein cholesterol (HDL-C) in all groups. There was a significant correlation between adiponectin and CRP levels in both hypothyroid and hyperthyroid groups. In all groups, adiponectin levels did not correlate with age, systolic blood pressure, diastolic blood pressure and thyroid hormones. Multiple regression analysis revealed BMI and HDL-C levels to be the most important predictors of circulating adiponectin levels.

CONCLUSIONS: Plasma adiponectin levels are associated with BMI and HDL-C levels in patients with hypothyroidism and hyperthyroidism. But there is not a direct relation of adiponectin with thyroid hormones in these patients.