Less Favorable Lipid Profile and Higher Prevalence of Thyroid Antibodies in Women of Reproductive Age with High-Normal TSH—Retrospective Study

Abstract

High-normal TSH can be associated with metabolic abnormalities and infertility. Aims of this study are to analyze retrospectively if routinely measured blood laboratory and anthropometric parameters differ between women of reproductive age with TSH < 2.5 mIU/L and with TSH ≥ 2.5 mIU/L. Retrospective analysis was performed in 466 female inpatients, aged 13–51, hospitalized in an endocrine department. The group of 280 patients with normal thyroid tests (TSH 0.27-4.2 mIU/L; normal FT3 and FT4) was selected and it was divided into two subgroups, i.e., with TSH < 2.5 mIU/L and TSH ≥ 2.5 mIU/L (n = 66; 23.6%). After excluding patients on L-thyroxine treatment (n = 240), those with TSH ≥ 2.5 mIU/L constituted 22.92% (n = 55). In the group of 280 patients with normal thyroid tests, an abnormally high concentration of triglycerides and an abnormally low HDLC/cholesterol ratio occurred more frequently in women with TSH ≥ 2.5 mIU/L than those with TSH < 2.5 mIU/L (17% vs. 7%, p = 0.017; 14% vs. 5%, p = 0.015, respectively). Increased concentration of thyroid antibodies, i.e., TPOAb, occurred more frequently in patients with TSH ≥ 2.5 mIU/L than those with TSH < 2.5 mIU/L (27% vs. 9%, p = 0.001). The same differences were found in the group of 240 patients after excluding those on L-thyroxine treatment. Blood lymphocyte concentration was the only independent linear parameter associated with TSH ≥ 2.5 mIU/L (OR = 1.551, p = 0.024) but only in the group of 280 patients with normal thyroid tests. TSH concentration correlated positively with blood lymphocyte (r = 0.129, p = 0.031) and TPOAb (r = 0.177, p = 0.005) concentrations but only in the group of 280 patients with normal thyroid tests. Less favorable lipid profiles and a higher prevalence of thyroid antibodies in women of reproductive age with high-normal TSH suggests that L-thyroxine treatment should be considered in such patients. The significance of a positive association between high-normal TSH and blood lymphocytes requires further evaluation.

Potential Risk Factors for Isolated Hypothyroxinemia in Women of Childbearing Age—Results from Retrospective Analysis

“…Such associations are expected concerning the mechanism of thyroid hormones action on lipid profile, and similar results were found by Knight and coworkers in a pregnant population [3]. It is worth mentioning that similarly to the association between IH and abnormal lipid profile, observed in the present analysis, we found the association between high normal TSH and abnormal lipid profile in the same population sample [25], and also in our earlier prospective studies performed in non-pregnant women of reproductive age [44,45]. Therefore, it can be concluded that both IH and high normal TSH (which is associated with only a relative decrease of thyroxine concentration) contribute to the abnormal lipid profile in women of childbearing age.…”

“…The steps of this retrospective study, including the patient characteristics, were described in detail elsewhere [25].…”

The Association between Thyroid-Stimulating Hormone and Long-Term Outcomes in Patients with ST Segment Elevation Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention

“…In some recent studies, researchers found that participants with high-normal TSH levels were associated with less favorable lipid profiles. 22 , 23 Li revealed that TSH within the reference range is positively associated with the risk of CAD; individuals with 2.5–5.5 mIU/L of TSH had a 4-fold risk of CAD compared with those with 0.3–0.9 mIU/L. 24 In our study, it was firstly concluded that TSH elevation within the normal range did not portend prognosis in STEMI.…”

Prevalence of thyroid dysfunction and thyroid autoimmunity in infertile women

“…Although still not recommended, a few studies have proposed lowering the threshold of TSH for diagnosing subclinical hypothyroidism from the conventional 4-5 mIU/L to 2-2.5 mIU/L [30][31][32][33][34] . Recently, women with high normal TSH levels (> 2.5 mIU/L) were found to have unfavorable lipid profile, oxidative damage of membrane lipids and low levels of mannanbinding lectin, all of which are associated to infertility and adverse pregnancy outcomes [32][33][34] . When using the lower threshold of 2.5 mIU/L, 70 (27.5 %) patients in this study could be considered hypothyroid.…”