Relationships between finger-length ratios, ghrelin, leptin, IGF axis, and sex steroids in young male and female swimmers.
The aim of this study was to investigate possible relationships between different right-hand finger-length ratios and different fasting hormone concentrations in young swimmers. Fifty-five young swimmers participated in this study (26 boys and 29 girls, aged 10-17 years). The original method of Visnapuu and Jürimäe (J Strength Cond Res 21:923-929, 2007) was used for the measurement of length parameters of the hand. The following finger-length ratios were calculated: 1D:2D, 1D:3D, 1D:4D, 1D:5D, 2D:3D, 2D:4D, 2D:5D, 3D:4D, 3D:5D, and 4D:5D. All finger-length ratios were significantly higher in girls compared with boys. Ghrelin, leptin, testosterone in boys, estradiol in girls, insulin-like growth-factor I (IGF-I), IGFBP-3, and insulin were analyzed. Leptin and insulin concentrations were lower in boys compared with girls. In both groups, the relationships between finger-length ratios and basic anthropometric parameters were not significant. In girls, estradiol correlated negatively with 2D:3D (r = -0.51) and 2D:4D (r = -0.49) finger ratios. In boys, ghrelin concentration correlated with most of the finger-length ratios (r = 0.37-0.40). In girls, the relationship of ghrelin with the 2D:3D (r = 0.45) and 2D:4D (r = 0.48) finger ratios was significant. In boys, but not in girls, IGF-I (r = 0.42) and IGFBP-3 (r = 0.44) correlated only with the 2D:4D finger ratio. Leptin and insulin did not correlate with the finger-length ratios. In boys, the most important hormone to characterize several finger-length ratios was ghrelin (13.7-15.6% variance accounted for). Ghrelin and testosterone together accounted for 20.3% (R (2) x 100) of the variance in the 2D:4D ratio. In girls, estradiol was correlated with the 2D:3D ratio (25.7%) and estradiol in combination with ghrelin with the 2D:4D ratio (30.0%). In conclusion, ghrelin appears to be a further biochemical parameter in addition to the sex steroids which correlated with different digit-length ratios at least in boys.
Jürimäe
T
T
Institute of Sport Pedagogy and Coaching Sciences, Faculty of Exercise and Sport Sciences, Centre of Behavioural and Health Sciences, University of Tartu, 18 Ulikooli Street, 50090 Tartu, Estonia. toivo.jurimae@ut.ee
Voracek
M
M
Jürimäe
J
J
Lätt
E
E
Haljaste
K
K
Saar
M
M
Purge
P
P
D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000097:blood*; D005215:Fasting / Q000097:blood; D005260:Female; D005385:Fingers / Q000033:anatomy & histology*; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D020738:Leptin / Q000097:blood*; D008297:Male; D012737:Sex Factors; D013550:Swimming; D013739:Testosterone / Q000097:blood*
D054439:Ghrelin; C515497:IGFBP3 protein, human; D007328:Insulin; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D020738:Leptin; D013739:Testosterone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I