Evaluation of Thyroid Function and Its Relationship With Metabolic Parameters in Indian Adolescents With PCOS

Background: Women with PCOS have high insulin resistance and a higher prevalence of raised TSH levels. Thyroid dysfunction can lead to the alterations in lipid and metabolic parameters. There is a very little data regarding the relationship between TSH and indices of insulin resistance in Indian adolescents with PCOS. Aim of Study: To assess the status of thyroid function and its impact on biochemical parameters and cardiovascular (CV) risk factors in Indian Adolescents with PCOS. Methods: Study group was 130 adolescents aged between 13 to 19 years, recently diagnosed with PCOS as per Revised Rotterdam criteria and a control group of 75 age matched, healthy, non PCOS females. Participants were subjected to an elaborate clinical, anthropometric and biochemical assessment. Hormonal analysis included serum FT3, FT4, TSH, anti-TPO antibody, LH, FSH, prolactin, free testosterone, 17 OH progesterone, Lipid profile. Fasting plasma glucose and Insulin were used to calculate HOMA-IR. Statistical analysis was done by SPSS. P value of <0.005 was significant. Results: Mean age of the subjects was 15.9 ± 3.1 years. Mean level of TSH was higher in PCOS group than in controls (4.1 ± 3.1 vs 2.8 ± 1.9; p-<0.001). There was significantly higher prevalence of subclinical hypothyroidism (SCH) (19.2%vs 6.7%;p-0.01), Anti TPO antibody titre (18.6 vs 4.7%; p,0.01) and goitre (14.1%vs 3.2%; p - 0.02) in PCOS subjects compared to controls. BMI and Systolic BP were higher in PCOS with SCH. Free testosterone (p-0.002), HOMA-IR (p- 0.03) and dyslipidaemia (p < 0.01) were significantly higher in PCOS subjects with SCH as compared to both euthyroid PCOS and euthyroid controls. Discussion: 50-70% women with PCOS, have been reported to have insulin resistance and hyperinsulinemia and are at a higher risk for developing metabolic and CV diseases. Literature supports the high prevalence of SCH/thyroid autoimmunity in PCOS. In this study we have found that Indian adolescents with PCOS have a high prevalence of SCH. Also we have observed significant changes in insulin resistance indices in PCOS subjects with SCH as compared to those with normal thyroid functions. The association between TSH level and insulin resistance indices is complex and one probable mechanism is that the hypothyroidism leads to increase in adiposity and pro inflammatory markers. This unique interplay of PCOS, adiposity, thyroid dysfunction and autoimmunity forms a complex pathophysiological pathway which leads to the potentiation of insulin resistance thereby resulting in a further increase in metabolic and CV risk in women with PCOS. Conclusion: There is a high prevalence of SCH in Indian Adolescents girls with PCOS and it is associated with significant changes in insulin resistance indices, which may increase the risk of metabolic and CV disorders in these already vulnerable young subjects.