Associations between thyroid function and gestational diabetes mellitus in Chinese pregnant women: a retrospective cohort study

Geng-Dong Chen,Dong-Xin Lin,Da-Zhi Fan,Li-Juan Wang,Xiao-Yan Gou,Ting-Ting Pang,Zi-Xing Zhou,Zheng-Ping Liu,Xiao-Ling Guo,Peng-Sheng Li

doi:10.1186/s12902-022-00959-y

Geng-Dong Chen, Dong-Xin Lin + Show 8 more

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https://doi.org/10.1186/s12902-022-00959-y

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Abstract

BackgroundThyroid function is known to be closely linked with type 2 diabetes, but data on the association between thyroid function and gestational diabetes mellitus (GDM) are inconsistent.MethodsA total of 2849 pregnant women were included in this retrospective study. Serum concentrations of thyroid indicators (free tetraiodothyronine, FT4; thyroid-stimulating hormone, TSH; and thyroid peroxidase antibody, TPO Ab) were obtained from a clinical laboratory. The presence of GDM were drawn from medical records. The clinical subtypes of thyroid function (euthyroidism, subclinical hypothyroidism, hyperthyroidism, and isolated hypothyroxinemia) were categorized according to the thresholds of the 2.5th/97.5th and 10th/90th percentiles of TSH and FT4 concentrations. A concentration of > 34 IU/L was defined as indicating TPO Ab-positivity.ResultsTwo hundred and thirty-five (8.25%) of the 2849 women were TPO Ab-positive. Higher serum concentrations of FT4 (top vs. bottom tertiles) was found to be negatively associated with the risk of GDM. The corresponding odds (OR) values (top tertile vs. bottom tertile) were 0.71 [95% confidence interval (CI): 0.54, 0.93]. No significant associations were observed between the extremely 2.5th/97.5th or 10th/90th percentiles of FT4 concentration, TSH concentration, thyroid function subtypes (vs. euthyroidism), TPO Ab-positivity (vs. -negativity), and the GDM risk. The corresponding results remained similar when TPO Ab-positive subjects were excluded.ConclusionsA negative association with the risk of GDM was observed for the highest FT4 concentrations tertile. No significant associations were found between the TSH concentration, thyroid function subtypes, TPO Ab positivity, and the GDM risk.

Highlights

Thyroid function is known to be closely linked with type 2 diabetes, but data on the association between thyroid function and gestational diabetes mellitus (GDM) are inconsistent
After adjustment for age, body mass index (BMI), parity, and gestational weeks of thyroid function or BMI measurement, subjects with the highest FT4 concentrations had a 29% lower risk of GDM
No significant associations were observed between thyroid-stimulating hormone (TSH) concentrations and the GDM risk in any of the adjusted models and among either total subjects or thyroperoxidase antibody (TPO Ab)-negative subjects

Summary

Introduction

Thyroid function is known to be closely linked with type 2 diabetes, but data on the association between thyroid function and gestational diabetes mellitus (GDM) are inconsistent. Gestational diabetes mellitus (GDM) is a major complication that may occur during pregnancy and greatly affects the health of mothers and infants [1]. Mothers with GDM have a higher risk of adverse birth outcomes [2, 3], and may be imposed to a seven-fold increased risk of type 2 diabetes mellitus (T2DM) in later life [4]. The prevalence of GDM has progressively increased in China, and occurs at a rate of 14.8% according to a recent report [5]. Several indicators are commonly used to measure thyroid function, namely the concentrations of free thyroxine (FT4), thyroid-stimulating hormone (TSH), and anti-thyroperoxidase antibody (TPO Ab). A person’s thyroid status (e.g., euthyroidism; subclinical hypothyroidism, SCH; isolated hypothyroxinemia; or hyperthyroidism) can be determined according to their relative concentrations of FT4 and TSH [10]

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