Context: Because of its anabolic and lipolytic properties, growth hormone (GH) use is prohibited in sport. Two methods based on population-derived decision limits are currently used to detect human GH (hGH) abuse: the hGH Biomarkers Test and the Isoforms Differential Immunoassay.
Objective: We tested the hypothesis that longitudinal profiling of hGH biomarkers through application of the Athlete Biological Passport (ABP) has the potential to flag hGH abuse.
Methods: Insulin-like growth factor 1 (IGF-1) and procollagen III peptide (P-III-NP) distributions were obtained from 7 years of anti-doping data in elite athletes (n = 11 455) and applied as priors to analyze individual profiles from an hGH administration study in recreational athletes (n = 35). An open-label, randomized, single-site, placebo-controlled administration study was carried out with individuals randomly assigned to 4 arms: placebo, or 3 different doses of recombinant hGH. Serum samples were analyzed for IGF-1, P-III-NP, and hGH isoforms and the performance of a longitudinal, ABP-based approach was evaluated.
Results: An ABP-based approach set at a 99% specificity level flagged 20/27 individuals receiving hGH treatment, including 17/27 individuals after cessation of the treatment. ABP sensitivity ranged from 12.5% to 71.4% across the hGH concentrations tested following 7 days of treatment, peaking at 57.1% to 100% after 21 days of treatment, and was maintained between 37.5% and 71.4% for the low and high dose groups 1 week after cessation of treatment.
Conclusion: These findings demonstrate that longitudinal profiling of hGH biomarkers can provide suitable performance characteristics for use in anti-doping programs.
Keywords: anti-doping; athlete biological passport; biomarkers; growth hormone.
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