Defining Hyperandrogenaemia According to the Free Androgen Index in Chinese Women: A Cross-Sectional Study

In the 2012 cross-sectional study of 1526 Chinese women aged 20-45, researchers established a reference range for the free androgen index (FAI) to define hyperandrogenaemia. The normative cut-off value for FAI was set between 0.7 and 6.4, based on the 5th and 95th percentiles from 444 women without known factors affecting androgen levels. A cut-off value of 6.1 was identified for the general population using K-means cluster analysis. The study revealed a negative correlation between FAI values and age (r = −0.185, P<0.0001), and a positive correlation with body mass index after age adjustment (r = 0.250, P < 0.0001). Higher FAI values were associated with increased risks for metabolic disorders. The study concluded that FAI values above 6.4 may indicate hyperandrogenaemia, which is linked to greater metabolic risks in Chinese women of reproductive age.