Author(s): ErotokritouMulligan I, Bassett EE, Cowan DA, Bartlett C, McHugh C,
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Abstract CONTEXT: A method based on the two GH dependent markers, IGF-I and procollagen III peptide (P-III-P) has been proposed to detect exogenously administered GH. As previous studies involved predominantly white European elite athletes, it is necessary to validate the method in other ethnic groups. OBJECTIVE: To examine serum IGF-I and P-III-P in elite athletes of different ethnicities within 2 h of competing at national or international events. DESIGN: Cross-sectional observational study. SETTING: National and International sporting events. SUBJECTS: 1085 elite athletes of different ethnicities. INTERVENTION: Serum IGF-I and P-III-P were measured and GH-2000 discriminant function score was calculated. Effect of ethnicity was assessed. RESULTS: In men, IGF-I was 21.7 +/- 2.6\% lower in Afro-Caribbeans than white Europeans (P < 0.0001) but there were no differences between other ethnic groups. In women, IGF-I was 14.2 +/- 5.1\% lower in Afro-Caribbeans (P = 0.005) and 15.6 +/- 7.0\% higher in Orientals (P = 0.02) compared with white Europeans. P-III-P was 15.2 +/- 3.5\%, 26.6 +/- 6.6\% and 19.3 +/- 5.8\% lower in Afro-Caribbean (P < 0.0001), Indo-Asian (P < 0.0001) and Oriental men (P = 0.001), respectively, compared with white European men. In women, P-III-P was 15.7 +/- 4.7\% lower in Afro-Caribbeans compared to white Europeans (P =0.0009) but there were no differences between other ethnicities. Despite these differences, most observations were below the upper 99\% prediction limits derived from white European athletes. All GH-2000 scores lay below the cut-off limit proposed for doping. CONCLUSIONS: The GH-2000 detection method based on IGF-I and P-III-P would be valid in all ethnic groups.
This article was published in Clin Endocrinol (Oxf)
and referenced in Journal of Bioequivalence & Bioavailability