Possible added value of thyroglobulin antibody (TgAb) testing in the evaluation of thyroidal status of subjects with overweight or obesity

The interplay between subclinical hypothyroidism and poor sleep quality: A systematic review

BACKGROUND

The relationship between subclinical hypothyroidism (SHYPO) and sleep disturbances is still poorly investigated. This systematic review aims to critically appraise the existing literature to provide more insights in understanding whether SHYPO favors sleep disturbances or it is the sleep disturbance per se that affects the hypothalamus-pituitary-thyroid axis regulation.

METHODS

Original studies on sleep quality and duration in patients with SHYPO were searched in the PubMed/MEDLINE, Embase, Web of Science and Scopus databases. Two reviewers independently screened articles for inclusion, extracted data, and assessed the quality of included studies.

RESULTS

Eight studies, including 2916 patients with SHYPO and 18,574 healthy controls, were retrieved. An overall agreement (7 out of 8 studies), about a positive correlation between decreased sleep quality and/or duration and SHYPO was observed. Five studies investigated sleep quality through self-reported surveys; only two studies explored both subjective and objective assessment of sleep quality with actigraphy (n = 1) or polysomnography (n = 1); finally, one study assessed subjective evaluation of sleep quality through a single question regarding the number of sleeping hours. A high level of heterogeneity among studies was manifest due to differences in population source, sleep measure assessment and criteria for diagnosing SHYPO.

DISCUSSION

Overall, the existing literature data suggest a link between SHYPO and sleep disturbances, but further studies on larger populations of patients with homogeneous study designs and outcomes are warranted.

Relationship between maternal obesity and first-trimester TSH in women with negative anti-TPO antibodies

Objective

Obesity is associated with increased thyroid-stimulating hormone (TSH) in non-pregnant subjects, but this phenomenon has not been fully characterized during pregnancy. Our aim was to evaluate the impact of BMI on first-trimester TSH in a wide cohort of pregnant women with negative anti-thyroperoxidase antibodies (AbTPO) and its implications on uterine artery pulsatility index (UtA-PI), a marker of early placentation.

Methods

The study included 2268 AbTPO-negative pregnant women at their first antenatal visit. Anamnestic data, BMI, TSH, anti-nuclear antibody (ANA) and extractable nuclear antigen (ENA) positivity and mean UtA-PI were collected.

Results

A total of 1693 women had normal weight, 435 were overweight and 140 were obese. Maternal age, ANA/ENA positivity, history of autoimmune diseases and familiar history of thyroid diseases were similar in the three groups. TSH was significantly higher in obese women (1.8 (IQR: 1.4-2.4) mU/L) when compared to normal weight (1.6 (IQR: 1.2-2.2) mU/L) and overweight (median: 1.6 (IQR: 1.2-2.2) mU/L) ones (P < 0.001). BMI was significantly related with the risk of having a TSH level ≥4 mU/L at logistic regression, independently from non-thyroid autoimmunity, smoking or familiar predisposition for thyroid diseases (OR: 1.125, 95% CI: 1.080-1.172, P < 0.001). A restricted cubic splines regression showed a non-linear relationship between BMI and TSH. Women with a TSH ≥4 mU/L had a higher UtA-PI, independently from BMI.

Conclusion

Overweight/obesity is significantly related with TSH serum levels in AbTPO-negative pregnant women, independently from the other risk factors for hypothyroidism during pregnancy. The increase of TSH levels could be clinically relevant, as suggested by its association with abnormal UtA-PI, a surrogate marker of abnormal placentation.

Association between the Systemic Immune-Inflammation Index and Thyroid Function in U.S. Adults

Background

The systemic immune-inflammation index (SII) is used as an indicator of prognosis for a wide range of diseases. Thyroid function has been found to be strongly associated with inflammation. The purpose of this investigation was to analyze the correlation between SII and various thyroid functions.

Methods

This study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2007-2012. The association between SII and thyroid function was analyzed using weighted univariate and multivariate linear regression analyses. Subgroup analyses, interaction tests, and weighted restricted cubic spline (RCS) regression analyses were also employed to test this correlation.

Results

Of the 6,875 participants (age ≥ 20 years), the mean age was 46.87 ± 0.40 years. The adjusted model showed that lnSII was negatively correlated with FT3 (β = -0.0559, 95% CI -0.1060 to -0.0059,) and FT3/FT4 (β = -0.0920, 95% CI -0.1667 to -0.0173,). There was a positive correlation between lnSII and TT4 (β = 0.1499, 95% CI 0.0722-0.2276,). In subgroup analyses, lnSII still independently affected a wide range of thyroid functions. Weighted RCS analysis showed a nonlinear relationship between FT3 and lnSII.

Conclusion

Close relationships exist between SII and a variety of thyroid functions. SII can be used as an indicator to predict thyroid dysfunction. Control of inflammatory activity may be a protective measure against thyroid dysfunction. More large-scale prospective studies are necessary to further explore the correlation between SII and thyroid function and the role of obesity in this.