Is autoimmune thyroiditis a risk factor for early atherosclerosis in premenopausal women even if in euthyroid status?

Abstract

Autoimmune thyroiditis (AIT) is a systemic disease. It is well-known that overt thyroid dysfunction is a cardiovascular risk factor. However, the influence of euthyroid status is unclear. The aim of this study was to evaluate the metabolic parameters and carotid intima-media thickness (CIMT) in euthyroid premenopausal women with AIT. Fourty-eight premenopausal women and 18 age-matched healthy controls attending the Endocrinology and Metabolism Clinic from 2008 to 2009 were enrolled to this cross-sectional study. Patients were divided into 2 groups according to TSH levels; patients in group 1 (n = 23) had TSH levels ≤ 2.5 μIU/mL and patients in group 2 had TSH levels > 2.5 μIU/mL (n = 25). All participants were evaluated by ultrasound for CIMT (mean of three segments in both carotid arteries) by the same experienced investigator. Fasting venous blood samples were collected to evaluate insulin resistance (HOMA-IR), TSH, FT4, plasma lipids, high-sensitive CRP (Hs-CRP), homocysteine, and fibrinogen. Carotid intima-media thickness was found to be significantly higher in patients than the controls (p < 0.001). However, there was no significant difference in average CIMT between group 1 and 2 (0.66 ± 0.08 vs 0.63 ± 0.09 mm). Anti-Tg levels were independently associated with CIMT in the patient group (p = 0.014). There were no significant correlations between serum TSH levels and BMI; waist circumference, serum lipids, and glucose levels. However, there was a positive significant correlation between TSH levels and blood pressure in the patients (for systolic blood pressure r = 0.466, p = 0.001, for diastolic blood pressure r = 0.372, p = 0.009). In the present study, it was shown that CIMT is increased in euthyroid premenopausal women with autoimmune thyroiditis compared to age-matched healthy controls.

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

“…Our results were partially in line with Tamer et al [35] who have concluded that the thyroid autoimmunity disorder can be proved to be correlated with hyperlipidemia and atherosclerosis, independent of the thyroid function. According to the study, the serum level of TPO Abs bears a negative relationship with HDL; which is confirmed in another study where a positive correlation between Anti-TPO Abs and cholesterol and LDL is also reported [36]. …”

Autoimmune thyroid disease: a novel risk factor for atherosclerosis?

“…It is, therefore, imperative that future high-quality evidence confirms or refutes that autoimmune thyroid disease is a risk factor for atherosclerosis. The current report by Topaloglu et al [14] reinforces this need.…”

“…In this issue of Endocrine, Topaloglu et al [14] add further evidence to the debate. This study recruited 48 euthyroid premenopaual women with Hashimoto's thyroiditis and compared them to 18 controls with respect to CIMT, cardiovascular risk factors, and metabolic parameters.…”

Serum homocysteine levels are decreased in levothyroxine-treated women with autoimmune thyroiditis

“…Currently, however, the causative relationship between thyroid autoimmunity and increased risk of atherosclerosis has not yet been established. A few studies which were addressing this question investigated the effect of thyroid autoimmunity on lipid profile, abdominal obesity, fasting glucose and homeostasis model assessment (HOMA) insulin resistance, as well as carotid intima-media thickness (CIMT) [25][26][27]. However, in contrast to our study group, the study populations were not uniform, therefore the conclusions of these investigations are not comparable.…”