Steroid profiles of professional soccer players: an international comparative study

Emmanuel Strahm ¹, Pierre-Edouard Sottas ¹, Carine Schweizer ¹, Martiel Saugy ¹, Jiri Dvorak ² and Christophe Saudan ^1*

¹ Swiss Laboratory for Doping Analysis, Switzerland
² FIFA Medical Assessment and Research Centre, Switzerland

^* To whom correspondence should be addressed. E-mail: christophe.saudan{at}chuv.ch.

Accepted 16 January 2009

Abstract

Background and objectives: Urinary steroid profiling is used in doping controls to detect testosterone abuse. A testosterone over epitestosterone (T/E) ratio exceeding 4.0 is considered as suspicious of testosterone administration, irrespectively of individual heterogeneous factors such as the athlete’s ethnicity. A deletion polymorphism in the UGT2B17 gene was demonstrated to account for a significant part of the inter-individual variability in the T/E between Caucasians and Asians. Here, we examined the variability of urinary steroid profiles in a widely heterogeneous cohort of professional soccer players. Method: The steroid profile of 57 Africans, 32 Asians, 50 Caucasians and 32 Hispanics was determined by gas chromatography-mass spectrometry. Results: Significant differences have been observed between all ethnic groups. After estimation of the prevalence of the UGT2B17 deletion/deletion genotype (African:22%; Asian:81%; Caucasian:10%; Hispanic:7%), ethnic-specific thresholds were developed for a specificity of 99% for the T/E (African:5.6; Asian:3.8; Caucasian:5.7; Hispanic:5.8). Finally, another polymorphism could be hypothesized in Asians based on specific concentrations ratio of 5a-/5b-androstane-3a,17b-diol in urine. Conclusion: These results demonstrate that a unique and nonspecific threshold to evidence testosterone misuse is not fit for purpose. An athlete's endocrinological passport consisting of a longitudinal follow-up together with the ethnicity and/or the genotype would strongly enhance the detection of testosterone abuse. Finally, additional genotyping studies should be undertaken to determine if the remaining unexplained disparities have an environmental or a genetic origin.