Free androgen index significant diagnostic marker for PCOS: Study
PCOS prevalence varies globally with higher rates observed among Indian women compared to other populations characterized by a variety of symptoms and health complications. PCOS is associated with high levels of androgenic hormones and presents a spectrum of clinical manifestations.
During puberty, hormonal changes include rising levels of cortical androgen stimulating hormones with increased GnRH release leading to elevated LH and FSH levels. This hormonal surge stimulates the ovaries promoting the development of Graafian follicles and the onset of menarche. The physiology of the ovary involves the growth of one dominant follicle which matures under the influence of FSH and LH, with androgens produced by the theca interna cells being aromatized into estrogen by granulosa cells.
PCOS involves several key pathophysiological aspects like ovarian androgen production, hyperinsulinemia, elevated LH levels and abnormal ovarian morphology. The ovaries in PCOS typically have numerous small follicles and increased stromal volume with an imbalance in follicle development and a high rate of atresia inhibition. Insulin resistance plays a crucial role, contributing to the overall pathology of PCOS and increasing the risk of associated conditions like diabetes and cardiovascular disease.
Hyperandrogenism, characterized by elevated levels of androgens such as testosterone and androstenedione often accompanies irregular menstrual cycles. This imbalance can lead to additional issues like endometrial hyperplasia due to unopposed estrogen. Hyperandrogenism in PCOS can be attributed to multiple factors including ovarian, adrenal gland abnormalities, elevated insulinemia and conditions like hypothyroidism. Ovarian hyperandrogenism is commonly linked to cortical stromal hyperplasia and overproduction of androgens by the theca cells of the ovaries.
Sex Hormone Binding Globulin (SHBG) regulates the availability of free testosterone in the bloodstream. SHBG levels are often decreased in PCOS with a normal range of 16-120 nmol/L. The Free Androgen Index (FAI) calculated by dividing total testosterone by SHBG is a valuable diagnostic marker for hyperandrogenism. An FAI greater than 10 indicates elevated levels of free testosterone which correlates with PCOS symptoms such as hirsutism and acne. Thus measuring these hormones and indices provides critical insights into diagnosing and managing PCOS effectively. This study aimed to evaluate the clinical profile and anthropometric factors in women with PCOS and their correlation with Free Androgen Index (FAI) levels.
A cross-sectional study included 92 PCOS women in tertiary care centre. FAI levels were measured from blood samples, clinical features, anthropometric data were measured and recorded. Statistical analysis was performed using SPSS-23, with a significance level set at 5%.
Significant associations were found between FAI levels and clinical features. Higher FAI values correlated with irregular menstrual cycles (p = 0.0001), hirsutism (p = 0.00001), acne (p = 0.0001), androgen alopecia (p = 0.0001), acanthosis nigricans (p < 0.05), a mixed diet (p = 0.00001), physical inactivity (p = 0.00001), obesity (p = 0.00001), increased waist-hip ratio (p = 0.0001) and PCOM on ultrasound (p = 0.00001). Elevated FAI levels were notably associated with the metabolic phenotype of PCOS.
Overall, the study underscores the multifaceted nature of PCOS, where age, socioeconomic status, lifestyle choices, and clinical symptoms intersect with hormonal profiles such as FAI. This study supports previous studies that free androgen index is robust marker for diagnosis of PCOS as it is found to be elevated with various clinical manifestation of PCOS.
Source: Varadhan et al. / Indian Journal of Obstetrics and Gynecology Research 2025;12(2):278–282
