Polycystic ovary syndrome (PCOS) is a complex and heterogeneous endocrine disease characterized by clinical or laboratory hyperandrogenism, oligo-anovulation and metabolic abnormalities, including insulin resistance, overweight or obesity, type II diabetes, dyslipidemia, and an increased risk of cardiovascular disease [9]. The most important clinical manifestation of PCOS is hyperandrogenism.
About 50–70% of these patients are hyperinsulinemic insulin resistant and suffer from metabolic syndrome, which alone increases the risk of type II diabetes and cardiovascular disease. Great importance has been attached to the relationship between insulin resistance and hypothyroidism for decades, and extensive studies have been conducted on these issues.
[10] stated that it is estimated that approximately 70% of women with PCOS are insulin resistant, but this figure is affected by frequent referral bias. He also suggested that hyperinsulinemia plays a role in increased androgen overproduction, with bidirectional links between insulin resistance and hyperandrogenism.
[11] emphasized that insulin resistance is an important feature that worsens the features of PCOS in women with PCOS.
[12] observed an interesting increase in the level of insulin resistance parameters even below very small decreases in thyroid hormone levels (59T1259T). These findings brought to mind the question of whether the intensity of hypothyroidism has an additional effect on insulin resistance, so they investigated whether HT accompanying PCOS would cause an additional ovarian increase in this situation.
[13] included forty-nine women with PCOS and 23 control groups in the analysis. showed that muscle sympathetic nerve activity (MSNA) and testosterone level, age and BMI were most significantly associated with PCOS status.
[14] found a significant relationship between BMI, HOMA, fasting blood glucose, and fasting glucose/insulin ratio (G/I ratio) between PCOS patients with and without insulin resistance. In addition, HOMA has been used to examine insulin resistance among PCOS patients of different ethnicities and in many articles dealing with insulin resistance in diabetics.
SHBG is a well-known marker of insulin resistance in diabetics [15] and low levels have been reported in adolescent girls (known to be at risk for PCOS and insulin resistance) [16]. It has been shown that lower SHBG levels are associated with lower G/I ratios and higher HOMA indices (consistent with insulin resistance) in women with PCOS [17].
Thyroid disorders, especially hypothyroidism, are more common in patients with PCOS. Subclinical hypothyroidism may exacerbate insulin resistance in PCOS patients [3].
[14] conducted a comparative study on insulin secretion, insulin resistance, and thyroid function in patients with polycystic ovarian syndrome with and without Hashimoto's thyroiditis. Patients with PCOS and HT had higher insulin secretion and IR levels, while free thyroxine and thyrotropin levels were found to be significantly lower than those without HT. found that the ratio of free thyroxine to thyrotropin was higher in HT patients. It has been shown that in patients with PCOS, HT may be associated with insulin resistance and relatively low thyroid function.
[3] included 19 (25.5%) of 75 PCOS patients with subclinical hypothyroidism and 56 (74.4%) euthyroid patients. The prevalence of insulin resistance was 22.7%, and it was found that 77.3% of the patients had no insulin resistance and were normal. showed that they could not find a relationship between insulin resistance and subclinical hypothyroidism in PCOS patients.
[18] characterized the appearance of more than 10 follicles 2–8 mm in size with enlarged ovaries and pearl necklace-like peripherally located due to the increase in stroma tissue by USG as PCOS. For this reason, the relationship between enlarged ovaries and PCOS, which is characterized by insulin resistance, was investigated. There are various studies on this subject.
[19] evaluated the relationships between ovarian volume and AMH, LH/FSH ratio, T concentrations and body mass index (BMI). While there was a significant relationship between BMI and ovarian volume and BMI and T, other hormone parameters did not find a significant relationship. There was a significant difference between the patients diagnosed with PCOS and the control group in terms of HOMA index, mean ovarian volume, fasting blood glucose, and FAI [20].
Many studies show the relationship between insulin resistance and hyperandrogenemia. In our study, volume increase was detected in at least one ovary of patients with high insulin resistance for patients with PCOS and patients with PCOS + HT. In addition, the addition of HT exacerbated this increase.