Thyroid stimulating hormone is associated with metabolic syndrome in euthyroid postmenopausal women

Objectives: The aim of this study was to investigate the relationship between thyroid stimulating hormone (TSH) and metabolic syndrome (MetS) in euthyroid postmenopausal women. Methods: We conducted a cross-sectional study of 2205 Korean postmenopausal women. Subjects who were not euthyroid were excluded. Fasting TSH, free thyroxine (FT4), insulin, glucose, and the level of insulin resistance, estimated by the homeostasis model assessment for insulin resistance (HOMA-IR) were measured. MetS was defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria. Results: TSH levels were associated with total cholesterol, LDL-cholesterol, triglycerides and diastolic blood pressure. Using a multiple linear regression analysis, LDL-cholesterol, and triglycerides levels were identified as independently associated with TSH. Multivariate logistic regression analysis determined that TSH levels strongly contributed to MetS. Compared with the lower most quartile (TSH, 0.3-1.44 mIU/L), the adjusted odds ratio for MetS was 1.95 in the upper most quartile (TSH, 2.48-4.00 mIU/L). The prevalence of MetS increased as the TSH quartile showed a gradual increase. Conclusion: We found a close relationship between TSH and MetS in euthyroid postmenopausal women. Therefore, more attention should be focused on postmenopausal women with high normal TSH levels for the management of cardiovascular disease.