High-normal thyroid stimulating hormone is a predictor of metabolic syndrome among young polycystic ovary syndrome women

Background and objectives High-normal thyroid stimulating hormone (TSH) (2.6–4.5 μIU/ml) is associated with metabolic syndrome (MetS) in population studies. We hypothesized that euthyriod polycystic ovary syndrome (PCOS) with TSH of higher than 2.5 had altered anthropometric, metabolic, and endocrine parameters as well as higher percentage of MetS compared with those with lower TSH levels. Patients and methods The present study included 60 young euthyroid PCOS women without any thyroid risk factors and 60 age-matched and BMI-matched healthy, fertile women. Anthropometric measurements were obtained, biochemical and hormonal assay were evaluated, and the homeostatic model assessment-insulin resistance was calculated. PCOS women were divided into high-normal TSH (group 1) and low-normal TSH (group 2) groups. MetS was defined according to National Cholesterol Education Program/Adult Treatment Panel III. Results Group 1 had significantly higher waist circumference, systolic blood pressure and diastolic blood pressure, total cholesterol, triglycerides, low-density lipoprotein cholesterol, fasting glucose, fasting insulin, homeostatic model assessment-insulin resistance, and free androgenic index and significantly lower high-density lipoprotein cholesterol, free thyroxin, and sex hormone binding globulin compared with both group 2 and healthy controls. In addition, group 1 (compared with group 2) had significantly higher percentage and higher risk of MetS [46.7 vs. 16.7%, P=0.01; odds ratio (OR)=4.4] and some of its components such as fasting glucose of at least 100 mg/dl (26.7 vs. 6.7%, P=0.03; OR=4.3), high-density lipoprotein cholesterol of less than 50 mg/dl (50 vs. 23.3%, P=0.03; OR=3.3), TG of at least 150 mg/dl (50 vs. 20%, P=0.01; OR=4), and near-significant higher percentage of both waist circumference of 88 cm or more and systolic blood pressure of at least 130 (P=0.06 for both, OR=3.25, 5, respectively). TSH level of 2.85 was the best threshold to indicate MetS risk (sensitivity=68%, specificity=88%, Youden index=0.56, area under the curve=0.81). Conclusion High-normal TSH PCOS women had increased risk of MetS. The optimal cut-off point for diagnosis of MetS was 2.85 µIU/ml.