Determinants of Bone Outcomes in Adolescent Athletes at Baseline: The PRO-BONE Study.
The determinants of areal bone mineral density (aBMD) and hip geometry estimates in adolescent athletes are poorly understood. This study aimed to identify the determinants of aBMD and hip geometry estimates in adolescent male athletes.



One hundred twenty-one men (13.1 ± 0.1 yr) were measured: 41 swimmers, 37 footballers, 29 cyclists, and 14 controls. Dual energy X-ray absorptiometry measured aBMD at lumbar spine, femoral neck and total body. Hip structural analysis evaluated hip geometry estimates at the femoral neck. Multiple linear regression examined the contribution of the sports practised, stature, lean and fat mass, serum calcium and vitamin D, moderate to vigorous physical activity, vertical jump and cardiorespiratory fitness with aBMD and hip geometry estimates.



Region-specific lean mass was the strongest positive predictor of aBMD (β = 0.614-0.931) and football participation was the next strongest predictor (β = 0.304-0.579). Stature (β = 0.235-0.380), fat mass (β = 0.189), serum calcium (β = 0.103), serum vitamin D (β = 0.104-0.139), and vertical jump (β = 0.146-0.203) were associated with aBMD across various specific sites. All hip geometry estimates were associated with lean mass (β = 0.370 - 0.568) and stature (β = 0.338-0.430). Football participation was associated with hip cross-sectional area (β = 0.322) and moderate to vigorous physical activity (β = 0.140-0.142). Cardiorespiratory fitness (β = 0.183-0.207) was associated with section modulus and cross-sectional moment of inertia.



Region-specific lean mass is the strongest determinant of aBMD and hip geometry estimates in adolescent male athletes. Football participation and stature were important determinants for aBMD and hip geometry estimates, whereas the contribution of the other predictors was site specific.
1Children's Health and Exercise Research Centre, Sport and Health Sciences, University of Exeter, UNITED KINGDOM; 2IGOID Research Group, University of Castilla-La Mancha, Toledo, SPAIN; 3Department of Kinesiology, Institute for Research and Technology, Physical Education and Sport Sciences, University of Thessaly, Trikala, GREECE; 4Department of Physical Education and Sport Sciences, Democritus University of Thrace, Komotini, GREECE; 5Department of Medical Imaging, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UNITED KINGDOM; 6University of Exeter Medical School, Exeter, UNITED KINGDOM; and 7Growth, Exercise, Nutrition and Development Research Group, University of Zaragoza, Zaragoza, SPAIN.
Dimitris
D
Vlachopoulos
Esther
E
Ubago-Guisado
Alan R
AR
Barker
Brad S
BS
Metcalf
Ioannis G
IG
Fatouros
Alexandra
A
Avloniti
Karen M
KM
Knapp
Luis A
LA
Moreno
Craig A
CA
Williams
Luis
L
Gracia-Marco
D015502:Absorptiometry, Photon; D000293:Adolescent; D001642:Bicycling / Q000502:physiology; D050218:Body Fat Distribution; D001827:Body Height; D015519:Bone Density; D002112:Calcifediol / Q000097:blood; D002118:Calcium / Q000097:blood; D005272:Femur Neck / Q000033:anatomy & histology; D005538:Football / Q000502:physiology; D006615:Hip / Q000033:anatomy & histology*; D006801:Humans; D008297:Male; D010809:Physical Fitness; D013550:Swimming / Q000502:physiology; D000067009:Youth Sports / Q000502:physiology*
D002112:Calcifediol; D002118:Calcium