Ethnicity matters in detecting steroid use
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Swiss researchers are calling for an end to the current steroid doping tests used in international sports because the tests do not account for genetic differences among various ethnic groups and may be inaccurate.
The study, published online today in the British Journal of Sports Medicine, comes at a time when steroid use has clouded the presumed accomplishments of numerous international sports stars, such as baseball slugger Barry Bonds, who awaits trial for tax evasion and perjury relating to his alleged steroid use.
Evidence of steroid abuse is determined by the ratio of testosterone to epitestosterone in the urine. The threshold for evidence of possible testosterone doping is set at four or above for all athletes. (Another test is required to confirm doping.) Previous research, however, has shown that variations in a particular gene, UGT2B17, affects metabolism and the rate at which testosterone is passed out of the body in urine. Differences in this measurement between men of white and Asian ethnic backgrounds have been documented.
In the new study, Swiss researchers demonstrated the inaccuracy of using a threshold of four for everyone. They added steroids to urine samples from 171 athletes: 57 men of black African ethnicity, 32 of Asian ethnicity, 32 of Hispanic ethnicity and 50 Caucasians. The men were soccer players between the ages of 18 and 36. The researchers found a variation in the UGT2B17 gene in 22% of the athletes, including eight out of 10 Asian men.
Based on the genetic variations, the researchers recalibrated the thresholds for suspected doping for each group and concluded an appropriate threshold would be 5.6 for men of black African ethnicity, 5.7 for Caucasians, 5.8 for Hispanics and 3.8 for Asian men.
A more accurate approach to steroid doping would take into account each individual’s genetic profile, said the study authors, from the Swiss Laboratory for Doping Analysis.
-- Shari Roan