Insulin resistance in hypothyroid patients under Levothyroxine therapy: a comparison between those with and without thyroid autoimmunity

Abstract

BackgroundA chronic inflammation resulting from an imbalance between pro-inflammatory and anti-inflammatory cytokines in Hashimoto’s thyroiditis (HT) might be responsible for IR in hypothyroidism. This study was performed to investigate a probable association between autoimmune background of hypothyroidism and IR.MethodsIn this clinical study, 63 subjects with Hashimoto’s thyroiditis and 49 subjects with post-ablation hypothyroidism were enrolled. All the participants were euthyroid for more than one year through Levothyroxine therapy. Serum concentrations of Thyroid-stimulating Hormone (TSH), Free Thyroxin (FT4, FT3), Anti-Thyroid Peroxidase Antibodies (Anti-TPO Abs), Total Cholesterol (TC), HDL-Cholesterol (HDL-C), Triglyceride (TG), Fasting Blood Glucose (FBG), and insulin levels were measured and Oral Glucose Tolerance Test (OGTT) was performed for all of the subjects. Participants with anti TPO levels more than 1000 IU /ml were classified as having highly positive antibodies.ResultsNo significant differences regarding to plasma insulin, glucose and lipid concentration, were detected between subjects with and without Hashimoto’s thyroiditis. However, subjects with highly positive Anti TPO Abs had higher prevalence of elevated fasting insulin level than those with lower titers of Anti TPO Abs and subjects without autoimmune background (94.1% vs. 62.8% and 71.4% respectively, P = 0.05). Subjects with highly positive titers of Abs also had a lower serum HDL-c levels than the rest of the subjects (40.6 ± 2.1 vs. 47.2 ± 1.7 and 47.4 ± 1.4, P = 0.04).ConclusionsThere is no obvious association between thyroid autoimmunity and metabolic indexes of hypothyroid patients. Only patients with Ani TPO antibody levels more than 1000 IU/ml may experience higher insulin level and less HDL-c with the same BMI.

Vitamin D Supplementation Changed Relationships, Not Levels of Metabolic-Hormonal Parameters in Autoimmune Thyroiditis

“…In the follow up of glycemia, insulinemia or HOMA IR the authors did not find differences between AIT andcontrols (Biyikli et al 2014, Mazaheri et al 2014). However, in patients with AIT with high anti TPO titres (more than 1000 IU/ml), higher basal insulinemia was found (Mazaheri et al 2014).…”

Serum levels of nitrite/nitrate, lipid profile, and Fasting Plasma Glucose and their associations in subclinical hypothyroid women before and after a two month treatment by levothyroxine

“…However, many studies relate overt hypothyroidism to IR [20,43,6], but it has less been paid attention in case of subclinical hypothyroidism. The effect of hormone replacement therapy on glucose and insulin metabolism of hypothyroid patients was formerly investigated, but not in the case of sHT; [4] found a high prevalence of IR in hypothyroid patients in comparison to euthyroid controls. The patients had IR even those who were in euthyroid state by assistance of levothyroxine therapy.…”

“…Subclinical hypothyroidism (sHT) is manifested by increased levels of serum TSH despite normal values of free thyroid hormones (fT 3 and fT 4 ) [1]. This condition mostly affects women and is an agedependent disorder [2] resulting in several health complications including: impaired glucose and insulin metabolism [3], dyslipidemia, and cardiovascular disorders [4].…”

“…This condition mostly affects women and is an agedependent disorder [2] resulting in several health complications including: impaired glucose and insulin metabolism [3], dyslipidemia, and cardiovascular disorders [4]. Insulin resistance and altered peripheral glucose disposal are the main reverse effects of sHT on carbohydrate metabolism [5], so that insulin resistance leads to increase in hepatic cholesterol production and also very low density lipoprotein (VLDL) against elevated clearance of high density lipoprotein (HDL) [6].…”

Hashimoto Thyroiditis and Dyslipidemia in Childhood: A Review

“…Results from studies in the adult population also indicate that L-T4 treatment could result in lowering of TPO-Ab levels in patients with AIT (104,105). This could also potentially lead to the improvement of the lipid profile, having in mind that thyroid autoimmunity with higher TPO-Ab levels is associated with an unfavorable lipid profile irrespective of thyroid function, in both children and adults (13,63,80,106,107).…”