Subclinical hypothyroidism may worsen metabolic health in PCOS patients

Subclinical hypothyroidism may worsen metabolic health in PCOS patients | Image Credit: © mi_viri - © mi_viri - stock.adobe.com.

Health outcomes in subclinical hypothyroidism

Polycystic ovary syndrome (PCOS) patients with subclinical hypothyroidism (SCH) are at an increased risk of endocrine and metabolic dysfunction vs those without SCH, according to a recent study published in the International Journal of Women’s Health.¹

Approximately 6% to 10% of reproductive-aged women are impacted by PCOS, experiencing symptoms such as acne, menstrual irregularities, infertility, and hirsutism. Additionally, PCOS patients are at an increased risk of SCH, which presents as increased thyroid-stimulating hormone (TSH) levels.²

“Despite this association, the endocrine and metabolic characteristics of PCOS patients with SCH remain controversial, and their potential interactions require further investigation,” wrote investigators.¹

Evaluating metabolism in PCOS patients

The study was conducted to determine the impact of SCH on metabolic parameters in PCOS patients. PCOS patients were diagnosed based on rare or absent ovulation, hyperandrogenism symptoms, and polycystic changes in the ovaries. The presence of at least 2 of these symptoms indicated PCOS.

PCOS patients aged 18 to 45 years, also presenting with SCH, cooperating with the tests, and with complete clinical data were included in the analysis. Those with menstrual disorders, hyperthyroidism or hypothyroidism, acute or chronic underlying disease, first menstruation within 3 years, pregnancy, or use of a drug impacting results within 3 months were excluded.

A single researcher performed all physical examinations. Patients’ medical history and physical characteristics were obtained through a questionnaire, and relevant anthropometric measurements included height, weight, hip circumference, and waist circumference. Body mass index (BMI) was measured as weight divided by height.

Thyroid hormone, lipid, and glucose data

Thyroid hormone data was obtained through fasting blood collected on the morning of the third to fifth day of the menstrual cycle following overnight fasting for 10 to 12 hours. Luteinizing hormone (LH), testosterone (T), follicle-stimulating hormone (FSH), estradiol (E2), and prolactin (PRL) were reported as sex hormone indicators.

Lipid indicators were also reported, including triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). Finally, glucose indicators included fasting blood glucose (FBG), fasting insulin (FINS), oral glucose tolerance test (OGTT), and homeostasis model assessment of insulin resistance (HOMA-IR).

Group comparisons and hormonal differences

There were 198 PCOS patients included in the final analysis, 40 of whom were in the SCH group and 158 were in the non-SCH group. Age, age at menarche, parity, PCOS duration, and SCH duration did not significantly differ between these 2 groups. However, a higher BMI and waist-to-height ratio were reported in SCH patients vs non-SCH patients.

No statistically significant differences in serum T levels were reported between groups. However, TSH, LH, and PRL levels were significantly higher in the SCH group, while FSH and E2 levels were significantly lower, highlighting how SCH may impact PCOS patients’ thyroid hormone and sex hormone levels.

Serum HDL-C, LDL-C, FBG, OGTT 1-hour, and OGTT 2-hour levels did not significantly differ between the 2 groups. However, the SCH group presented with increased serum TG, TC, FINS, and HOMA-IR levels compared to the non-SCH group, highlighting a potential impact of SCH on glycolipid metabolism.

Implications

These results indicated an association between SCH and endocrine and glycolipid metabolism abnormalities in PCOS patients. This primarily presents as sex hormone, thyroid hormone, and glucose and lipid metabolism.

“Determining thyroid function is of great significance for PCOS patients,” wrote investigators. “In future clinical work, thyroid-related functional status tests should be conducted in PCOS patients to mitigate endocrine and metabolic disturbances caused by combined SCH.”

References

1. Dai F, Wu Z, Qin S, et al. The influence of subclinical hypothyroidism on endocrine and metabolic characteristics in patients with polycystic ovary syndrome. Int J Womens Health. 2025;17:1019-1026. doi:10.2147/IJWH.S517997
2. Bonakdaran S, Milani N, Khorasani ZM, Hosseinzadeh M, Kabiri M. Is there a relation between hypothyroidism and polycystic ovary syndrome and its metabolic components? Current Diabetes Rev. 2023;19(2):e260422204034. doi:10.2174/1573399818666220426090324