Subclinical hypothyroidism in patients with polycystic ovary syndrome: distribution and its association with lipid profiles

Prevalence of subclinical hypothyroidism in polycystic ovary syndrome and its impact on insulin resistance: a systematic review and meta-analysis

BACKGROUND

Although recent studies indicate a high prevalence of subclinical hypothyroidism (SCH) in women with polycystic ovary syndrome (PCOS), the reported prevalence rates vary widely. Therefore, we conducted this study to estimate the pooled prevalence of SCH among women with PCOS. Additionally, emerging evidence suggests that SCH may negatively impact insulin resistance in PCOS. Thus, we examined its effect on insulin resistance indices as our secondary objective.

METHODS

We searched PubMed, Web of Science, Scopus, and Embase from their inception to February 25, 2024. Observational studies reporting the prevalence of SCH among women with PCOS were included. Joanna Briggs Institute's (JBI) critical appraisal checklist for prevalence studies was adopted for the risk of bias assessment. The random-effects model was employed to estimate the pooled prevalence with its 95% confidence intervals (CI). The weighted mean difference (WMD) was used to compare the insulin resistance indices between PCOS patients with and without SCH.

RESULTS

Twenty-nine studies comprising 5765 women with PCOS were included. The meta-analysis demonstrated that 19.7% (95% CI: 16.1%; 23.5%) of women with PCOS have SCH. PCOS patients with SCH had significantly higher HOMA-IR (WMD = 0.78, 95% CI: 0.34; 1.22) and fasting insulin (WMD = 2.38, 95% CI: 0.34; 4.42) levels than those without SCH. Differences in fasting plasma glucose and 2-hour postprandial glucose did not reach statistical significance.

CONCLUSION

This systematic review and meta-analysis found that approximately 20% of women with PCOS have SCH. This underscores the need for regular thyroid function testing in these patients. The prevalence of SCH is influenced by the TSH cut-off used for diagnosis, highlighting the need for establishing a standardized TSH cut-off value. Furthermore, SCH significantly elevates the HOMA-IR index and fasting insulin levels, highlighting its potential impact on insulin resistance. Whether these metabolic changes are clinically important and put these individuals at higher risk of developing type 2 diabetes mellitus and cardiovascular disease requires further investigation.

SYSTEMATIC REVIEW REGISTRATION NUMBER IN PROSPERO

CRD42024510798.

CLINICAL TRIAL NUMBER

Not applicable.

Thyroid autoimmunity in different phenotypes of polycystic ovary syndrome: a single-center experience

PURPOSE

Polycystic ovary syndrome (PCOS) has been associated with Hashimoto's thyroiditis (HT) and 4 phenotypes have been described in this syndrome. The aim of this work was to investigate the frequency of anti-thyroid antibodies (TAb) and thyroid function in the 4 phenotypes of PCOS.

PATIENTS

This study included 448 patients with PCOS: 260 (58.0%) with phenotype A, 119 (26.6%) with phenotype B, 38 (8.5%) with phenotype C and 31 (6.9%) with phenotype D.

RESULTS

TAb positivity was detected in 90/448 patients (20.1%) and was statistically significant higher (p = 0.03) in the grouped phenotypes A-B (83/379, 21.9%) than in phenotypes C-D (7/69, 10.1%). Positive anti-thyroglobulin antibodies (TgAb) were detected in 74/448 (16.5%) patients and positive anti-thyroperoxidase antibodies (TPOAb) in 66/448 (14.7%) patients. Both TgAb and TPOAb positivity was higher but not statistically significant in phenotype A-B than phenotype C-D. High titer TgAb (> 100 UI/ml) frequency was significantly higher (p = 0.005) in grouped phenotypes A-B (39/379, 10.3%) than in phenotypes C-D (0/69, 0.0%), while no significant difference was observed for low titer TgAb (≤ 100 UI/ml). According to a binary logistic regression analysis hypothyroidism was significantly associated with TAb positivity (OR 4.19; CI 2.25-7.79; p < 0.01) but not with PCOS phenotype. Androgen profile was not associated with TAb positivity.

CONCLUSION

A higher frequency of positive TAb and of high titer TgAb and TPOAb have been detected in PCOS women with phenotypes A and B, probably in relation to the greater imbalances between estrogen and progesterone levels present in these phenotypes.

The Influence of Treated and Untreated Subclinical Hypothyroidism on Metabolic Profile in Women with Polycystic Ovary Syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) and hypothyroidism are the most common endocrinological disorders among women of reproductive age. Since hypothyroidism occurs more frequently in PCOS patients, it is vital to explain its clinical impact.

AIM

To evaluate the impact of subclinical hypothyroidism (SCH) and its treatment on the metabolic profile of patients with PCOS.

METHODS

190 women with PCOS phenotype A were enrolled in the case-control study. They were divided into three groups: 38 women with PCOS and subclinical hypothyroidism, 76 women with PCOS and SCH under thyroid replacement therapy, and 76 women with PCOS and normal thyroid function (control group). Serum lipids, fasting glucose, and insulin, as well as oral glucose tolerance tests were performed.

RESULTS

In the analyzed parameters, there were no statistic differences between the groups in relation to thyroid function. BMI turned out to be the main factor dividing the patients in terms of serum lipids, fasting glucose, fasting insulin, and oral glucose tolerance test. TSH was associated with total cholesterol and LDL cholesterol levels, whereas BMI has a dominant impact on HDL cholesterol, triglycerides, glucose, and insulin resistance.

CONCLUSIONS

SCH is associated with mild lipid serum alterations in women with PCOS, but it is BMI to have a dominant impact on glucose and insulin. It seems that treatment of SCH in PCOS does not significantly alter lipid and glucose metabolism.

Genetic Susceptibility to Joint Occurrence of Polycystic Ovary Syndrome and Hashimoto's Thyroiditis: How Far Is Our Understanding?

Polycystic ovary syndrome (PCOS) and Hashimoto’s thyroiditis (HT) are endocrine disorders that commonly occur among young women. A higher prevalence of HT in women with PCOS, relative to healthy individuals, is observed consistently. Combined occurrence of both diseases is associated with a higher risk of severe metabolic and reproductive complications. Genetic factors strongly impact the pathogenesis of both PCOS and HT and several susceptibility loci associated with a higher risk of both disorders have been identified. Furthermore, some candidate gene polymorphisms are thought to be functionally relevant; however, few genetic variants are proposed to be causally associated with the incidence of both disorders together.

Metabolic, Hormonal, Immunologic, and Genetic Factors Associated With the Incidence of Thyroid Disorders in Polycystic Ovarian Syndrome Patients

Many endocrinopathies have been increasingly affecting females of reproductive age. Polycystic ovary syndrome (PCOS) and hypothyroidism are some of the most common endocrinopathies seen in females. The aim of this study is to find a relationship between the incidence of thyroiditis in polycystic ovarian syndrome patients. Literature review search was conducted via a series of systematic searches using multiple databases which lead to cross-referencing of articles within assigned criteria. Our study resulted in a review of 42 articles pertaining to our study. In this literature review article, factors were identified associating PCOS with thyroiditis. A viable relationship was found between the incidence of PCOS and thyroiditis. The combination of factors seen in this study proposes that clinicians may need to focus on certain markers regarding the screening of the incidence of thyroiditis. We also recommend future cohort studies to be conducted to further confirm the associations identified in this article.

Impact of Subclinical Hypothyroidism on Reproductive and Metabolic Parameters in Polycystic Ovary Syndrome - A Cross-sectional Study from Bangladesh

INTRODUCTION

Separately, polycystic ovary syndrome (PCOS) and subclinical hypothyroidism (SCH) exert adverse effects on several reproductive and metabolic parameters; however, in conjunction, their effects are unclear. This study evaluated the impact of SCH on reproductive and metabolic parameters in women with PCOS.

METHODS

In this cross-sectional study, women with newly diagnosed PCOS were evaluated. Data on their clinical presentation and anthropometric measurements were recorded, in addition to oral glucose tolerance test, fasting lipid profile, serum thyroid-stimulating hormone (TSH), free thyroxine (FT4) and anti-thyroid peroxidase (anti-TPO).

RESULTS

Four hundred and sixty-five women, aged 12-40 years, with PCOS were included in this study; 10.8% of them had SCH and 18.3% were positive for anti-TPO. All participants had statistically similar mean age, body mass index (BMI), waist circumference, systolic blood pressure (BP) and diastolic BP. A similar number of participants in both the euthyroid PCOS and PCOS-SCH groups had menstrual irregularity, acne, subfertility, a first-degree family member with thyroid dysfunction, acanthosis nigricans and elevated BP. Participants with SCH-PCOS had a lower modified Ferriman-Gallwey score and hirsutism frequency, though serum total testosterone levels were similar in the two groups. More subjects in the SCH group were overweight/obese, and had central obesity and goiter compared to the euthyroid group. Blood glucose, lipids and prolactin levels were similar between the two groups; the frequencies of dysglycaemia and dyslipidaemia were also similar. A higher frequency of metabolic syndrome was observed in the SCH group, though the difference was not statistically significant (p=0.098).

CONCLUSION

In women with PCOS, the presence of SCH does not amplify the risk of metabolic and reproductive dysfunctions.

High Thyroid Stimulating Hormone Level Is Associated With Hyperandrogenism in Euthyroid Polycystic Ovary Syndrome (PCOS) Women, Independent of Age, BMI, and Thyroid Autoimmunity: A Cross-Sectional Analysis

Background: Infertility and dyslipidemia are frequently present in both women with polycystic ovary syndrome (PCOS) and subjects with thyroid dysfunction. Limited study regarding the association between thyroid stimulating hormone (TSH) level and phenotypes in euthyroid PCOS women. We aimed to determine whether the variation of TSH level associates with phenotypes in euthyroid PCOS patients. Methods: Cross-sectional study including 600 PCOS and 200 age, body mass index (BMI), and thyroid autoimmunity-matched Chinese women from Renji hospital, Shanghai Jiaotong university during January 2010 and August 2018. The anthropometric and serum biochemical parameters related to TSH, thyroid autoimmunity, lipid profiles, and sex steroids were detected. Results: The TSH level is higher in (2.29 ± 1.24 vs. 1.86 ± 0.90 mu/L, p < 0.001) in PCOS than controls. In euthyroid PCOS patients, TSH, TG, TC, LDL-c, and apoB level increased from non-hyperandrogenism (nonHA) to HA group (all p < 0.05). TSH level is positively associated with TG, apoB, free T, FAI, and negatively associated with apoA (all p < 0.05). The percentage of HA increased from TSH level (57.93% in TSH < = 2.5 group vs. 69.46% in TSH > 2.5 mU/L group, p = 0.006). HA phenotype is increased with TSH level independently of age, BMI, WC, LDL-C. Besides, in multivariate logistic regression analysis TSH and TG significantly associated with HA phenotype. Conclusions: Higher TSH level is associated with increased prevalence of HA phenotype independent of age, BMI and thyroid autoimmunity in euthyroid PCOS.

Clinical, Hormonal, and Metabolic Parameters in Women with Subclinical Hypothyroidism and Polycystic Ovary Syndrome: A Cross-Sectional Study

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in reproductive age women, yet its clinical presentation shares similarities with several other endocrine disorders such as thyroid disease. Hence, the objective of this study was to further evaluate this association by investigating the clinical, hormonal, and metabolic parameters between subclinical hypothyroidism (SCH) and PCOS.

METHODS

This is a cross-sectional study conducted in a tertiary care clinic at Cleveland, Ohio, USA. A total of 137 women diagnosed with PCOS by Rotterdam criteria were examined. SCH was defined as thyroid-stimulating hormone >2.5 mIU/L in the absence of symptoms of overt hypothyroidism. The mean age, body mass index (BMI), fasting plasma glucose (FPG), glucose tolerance test, hemoglobin A1c, fasting insulin, a 2 hours insulin level after 75 g glucose load, cholesterol, LDL, HDL, and homeostatic model assessment (HOMA) were compared between women with and without SCH. Logistic regression was used to adjust for age and BMI.

RESULTS

Among 137 women with PCOS, 21.9% had SCH. Comparison groups were similar in both age and BMI and there was no difference in the mean values of all endocrine and metabolic parameters tested. However, abnormal FPG levels (OR 3.01; CI: 1.12-8.07. p = 0.03) and abnormal HOMA (OR 3.7; CI: 1.14-12.00. p = 0.03) were more likely in women who had SCH than in women without SCH independent of age and BMI.

CONCLUSIONS

Women with PCOS and SCH are more likely to have impaired FPG values and impaired insulin sensitivity even after adjusting for age and BMI. Hence, close monitoring of PCOS patients for SCH may be beneficial.

Subclinical Hypothyroidism in Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis

Background: The association between subclinical hypothyroidism (SCH) and polycystic ovary syndrome (PCOS) has been reported in several studies, but it is not well-recognized. The aim of this study was to evaluate the prevalence of SCH in women with PCOS. Methods: An extensive literature search was conducted in PubMed, Embase, Web of Science, and Cochrane Library databases. All articles published before May 2018 was considered for eligibility. No language restrictions were implemented. The prevalence of SCH in PCOS was calculated by the meta-analysis to produce an odds ratio (OR) with 95% confidence interval (CI). Results: A total of 6 studies including 692 PCOS patients and 540 controls were eligible for the meta-analysis. The combined odds ratio (OR) of SCH risk for women with PCOS compared with controls was 2.87 (95% CI = 1.82-9.92; P < 0.000001). The OR increased to 3.59 when limiting thyroid stimulating hormone (TSH) cut-off to ≥4 mIU/L. Conclusions: Women with PCOS are more likely to develop SCH.

Subclinical Hypothyroidism Impact on the Characteristics of Patients with Polycystic Ovary Syndrome. A Meta-Analysis of Observational Studies

BACKGROUND/AIMS

Definitive polycystic ovary syndrome (PCOS) diagnosis should exclude thyroid dysfunctions. The purpose of the study is to examine the impact of subclinical hypothyroidism on the characteristics of PCOS patients.

METHODS

A meta-analysis of the published observational studies was conducted. Medline, Scopus, and Cochrane database search was performed to identify the studies that compared euthyroid PCOS and subclinical hypothyroidism (SCH)-PCOS patients. A total of 9 studies were selected, totalizing the inclusion of 1,537 euthyroid PCOS and 301 SCH-PCOS. The data were expressed as raw mean difference and standard error, using the random-effects model. Heterogeneity among studies was examined using the Cochran's test (Q) and I2 statistics.

RESULTS

Anthropometrical parameters were similar in both groups. Total cholesterol (TC) and triglyceride (TG) were higher in SCH-PCOS (p = 0.036 and p = 0.012). High-density lipoprotein cholesterol was lower in the SCH-PCOS group (p = 0.018). Fasting glucose was lower in euthyroid PCOS (p = 0.022). All androgen levels were similar in both group (p > 0.05 for all).

CONCLUSION

TC, TG and fasting glucose were higher in SCH-PCOS patients. Because of the heterogeneity among studies, some summarized results should be interpreted with caution. Consistent data for future studies addressing PCOS diagnosis are provided.

MANAGEMENT OF ENDOCRINE DISEASE: The impact of subclinical hypothyroidism on anthropometric characteristics, lipid, glucose and hormonal profile of PCOS patients: a systematic review and meta-analysis

OBJECTIVE

Subclinical hypothyroidism (SCH) is encountered in 10-25% of women with PCOS. To date, it remains unclear whether this coexistence influences the severity of metabolic and hormonal profile of these patients. The purpose of our systematic review is to investigate this potential relation.

METHODS

We systematically searched Medline, Scopus, ClinicalTrials.gov, Cochrane Central Register of Controlled Trials (CENTRAL) and Google Scholar databases together with reference lists from included studies. All prospective and retrospective observational cohort studies that investigated the impact of subclinical hypothyroidism on hormonal and metabolic parameters of PCOS patients were included. The methodological quality of studies was assessed with the Ottawa-Newcastle criteria. Statistical meta-analysis was performed with the RevMan 5.3 software.

RESULTS

Twelve studies were finally included in the present review, which enrolled 2341 PCOS patients. Among them, 577 had subclinical hypothyroidism, whereas the remaining 2077 were PCOS women with normal thyroid function. The presence of SCH significantly affected HDL (MD -3.92 mg/dL 95% CI: -6.56, -1.29) and triglycerides levels (26.91 mg/dL 95% CI: -3.79, 50.02). HOMA-IR was also affected (MD 0.82 95% CI: 0.15, 1.50). On the other hand, LDL, fasting glucose and 2-h OGTT were not influenced. Similarly, prolactin, FSH, LH, LH/FSH ratio and sex hormone-binding globulin remained unaffected.

CONCLUSION

Subclinical hypothyroidism does not influence the hormonal profile of women with PCOS. On the other hand, it results in mild metabolic abnormalities, which are not clinically important in a short-term setting.

IS SUBCLINICAL HYPOTHYROIDISM IN PATIENTS WITH POLYCYSTIC OVARY SYNDROME ASSOCIATED WITH BMI?

Objective

To investigate the impact of body weight on the subclinical hypothyroidism observed in patients with PCOS.

Methods

The study included 95 normal weight (Group-1) and 122 overweight or obese women (Group-2) with PCOS. The control group consisted of age and BMI matched healthy individuals and grouped as normal weight (n: 66, Group-3) and overweight or obese (n: 65, Group-4. Women with chronic disease such as overt thyroid dysfunction, late-onset adrenal hyperplasia, and diabetes were excluded from the study. Plasma glucose and lipid profile, thyroid hormones, insulin, FSH, LH, total testosterone, estradiol, progesterone and DHEA-S were measured.

Results

While fasting glucose was similar, insulin and HOMA-IR were higher in Group-2 and Group-4 (p: 0.001). The groups were similar with respect to FSH, Estradiol, prolactine, DHEAS. While total testosterone and LH levels were higher (ptestosterone: 0,009), progesterone was lower in both PCOS groups (pprogesterone: 0.041). Free T3, free T4, thyroid antibodies were similar between the groups, but the prevalence of subclinical hypothyroidism was greater in Group-2 and -4 than in Group-1 and -3 (p: 0.044). TSH was only correlated with BMI (r: 0.122, p: 0.02).

Conclusion

The increased prevalence of subclinical hypothyroidism in women with PCOS might be the result of increased BMI.