Kang Mi Lee (Korea Institute of Science and Technology)

Kang Mi Lee (Korea Institute of Science and Technology)

Yinglan Xu (Korea Institute of Science and Technology)

Mijin Jeon (Korea Institute of Science and Technology)

Sunmi Jung (Korea Institute of Science and Technology)

Kang Mi Lee (Korea Institute of Science and Technology)

Ethnic and genetic factors, such as UGT2B17 deletion polymorphism, are known to influence steroid metabolism and may affect anti-doping test interpretations. This study aimed to establish reference values for endogenous steroids in Korean athletes and to evaluate suspicious samples using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C/IRMS).

Urine samples from 4,721 Korean athletes (3,123 males and 1,598 females) were analyzed throughout 2024. Six endogenous steroids—testosterone (T), epitestosterone (E), 5α-androstane-3α,17β-diol (5αAdiol), 5β-androstane-3α,17β-diol (5βAdiol), etiocholanolone (Etio), and androsterone (A)—were quantified, and sex-specific box plots were generated. The results revealed that Korean athletes generally exhibit lower steroid concentrations than Caucasian populations, with significantly reduced levels observed in female athletes. This is consistent with the high prevalence of UGT2B17 deletion in East Asian populations.

Based on the steroid profile data, 35 samples (T/E ≥ 4.0 or outside individual thresholds set by the adaptive model) underwent GC-C/IRMS analysis. All samples were found to be negative for exogenous steroid use, yielding no Adverse Analytical Findings (AAFs). For these samples, δ13C values were determined for the six target steroids, and descriptive statistics including mean, median, standard deviation, maximum, and minimum were calculated.

This large-scale dataset enables the establishment of Korean population-specific reference values for endogenous steroid profiles. It supports improved interpretation within the framework of the Athlete Biological Passport (ABP) and highlights the importance of integrating ethnic and genetic considerations into anti-doping strategies. Our findings reinforce the need for population-adapted thresholds when applying both traditional steroid profiling and confirmatory GC-C/IRMS methods.