Subclinical Hypothyroidism may be Associated with Elevated High-sensitive C-Reactive Protein (Low Grade Inflammation) and Fasting Hyperinsulinemia

Abstract

Abstract. The ssociation between coronary heart disease and subclinical hypothyroidism (SCH) is unclear. We aimed to determine hs-CRP concentrations in patients with SCH. Seventy-seven patients (age 34.6 ± 13.7 yr) with SCH (TSH >4.2 mIU/ml and serum free thyroxine level between 0.932-1.71 ng/dL), and 80 control subjects (age 33.9 ± 13.3 yr) were studied. Thyroid hormones, C-reactive protein, insulin, glucose, total, HDL, LDL and VLDL-cholesterol levels and HOMA-IR index were also determined. TSH levels of SCH group were higher than control (7.4 ± 2.9 and 1.55 ± 0.78 mIU/ml, respectively, p = 0.0001). However, FT4 levels were lower than control subjects (1.18 ± 0.22 ng/dL and 1.38 ± 0.26, respectively, p = 0.001). Serum hs-CRP levels of subjects with SCH were higher than control subjects (4.2 ± 0.8 mg/l and 1.05 ± 0.3 mg/l respectively, p = 0.0001). Insulin levels of SCH group were higher than control (8.5 ± 4.3 mU/ml and 7.1 ± 3.1 mU/ml respectively, p<0.02) but, Homa-IR levels of the two groups were not different. Mean total and LDL-cholesterol levels of SCH group were higher than control (p = 0.01 and p<0.02). We also found a positive correlation between hs-CRP levels and insulin (r = 0.362, p = 0.002 in men, r = 0.358, p = 0.0001 in women), TSH (r = 0.611, p = 0.0001 in men, r = 0.411 p = 0.0001 in women), and prolactin (r = 0.340, p = 0.01 in men r = 0.553, p = 0.0001 in women). Conclusions: Patients with SCH, irrespective of gender, have higher serum hs-CRP, insulin, total and LDL-cholesterol levels than healthy subjects. 2-High hs-CRP level, and thereby low grade inflammation may be associated with fasting hyperinsulinemia before insulin resistance becomes evident in patients with SCH.

Association between subclinical hypothyroidism and severe diabetic retinopathy in Korean patients with type 2 diabetes

“…Our study revealed that HOMA-IR was higher in the SCH group than in the euthyroid group. This is consistent with previous studies showing fasting hyperinsulinemia or insulin resistance in patients with SCH [21,22]. Several studies have found that the presence of proliferative diabetic retinopathy is associated with insulin resistance in type 1 and type 2 diabetes [23,24].…”

Association Analyses of Variants in the DIO2 Gene with Early-Onset Type 2 Diabetes Mellitus in Pima Indians

“…In contrast, studies in hypothyroid conditions show a decrease in both hepatic insulin resistance (12) and insulin-mediated glucose uptake in muscles (10,12). In humans, subclinical hypothyroidism is associated with hyperinsulinemia (15).…”

TSH and free thyroxine concentrations are associated with differing metabolic markers in euthyroid subjects

“…The association between SCH and individual cardiovascular risk factors has also been explored, with discordant results (4)(5)(6). Even more controversial is the association between SCH and insulin resistance (7).…”