Trabecular and cortical bone separately assessed at radius with a new ultrasound device, in a young adult population with various physical activities.

The aim was to evaluate a new ultrasound device in a young adult population and to assess its reproducibility via comparison to DXA measurements and geometrical measurements from high-resolution radiographs. Ninety-three subjects aged between 20 and 51 years were recruited and divided into four groups according to their gender and physical activity status: 22 male athletes, 19 male controls, 21 female athletes, and 31 female controls. Ultrasonic measurements were assessed by the prototype LD-100 (Oyo Electric Co., Kyoto, Japan) on the dominant distal radius. Attenuation in the radius (dB), cortical bone thickness (mm), radius thickness (mm), mass density of cancellous bone (mg/cm(3)), and elasticity (GPa) of cancellous bone were obtained. BMD was measured by DXA at the dominant distal radius. Radius images were obtained with a direct high-resolution digital X-ray device (BMA, D(3)A Medical Systems), and radius and cortical thicknesses were estimated using a specific software (ImageJ, Bethesda, USA), in an area site-matched with LD-100. There was a significant positive correlation between site-matched BMD measurement and LD-100 parameters (p<0.004), X-ray radius thickness, and LD-100 parameters except elasticity (p<0.05, r>0.32), X-ray cortical thickness and LD-100 attenuation and cortical thickness (p<0.01). A significantly higher attenuation, cortical and radius thicknesses were found in athletes compared to controls (p<0.05). The radius thickness measured on radiographs was significantly higher in athletes versus controls in both sexes, and cortical thickness was significantly higher in male athletes versus controls. These data suggest a positive influence of physical activity on bone cortical measurements. This study also confirmed the particular interest of bone assessment by ultrasound.

Hypoleptinaemia in extreme body mass models: the case of international rugby players.

Leptinaemia has been poorly studied in athlete populations with the consequences of athletic hypoleptinaemia yet to be examined. Our aim was to determine if systemic leptinaemia is influenced in high body mass athletes. We recruited 24 rugby players (21.5+/-4.7 years; 11.8+/-2.9h/week) and 26 controls (22.3+/-3.1 years; 1.9+/-1.4h/week). BMD (whole body (WB), limbs, lumbar spine and non-dominant femur) and body composition (WB Lean Mass (LM) and FM) were measured by Dual X-ray Absorptiometry. Circulating levels of serum leptin (ng/ml), adiponectin (microg/ml), insulin (ng/ml), osteocalcin (ng/ml) and CTx (ng/ml) were assessed by ELISA assays. BMD were significantly higher in rugby players vs controls, at all bone sites, yet after adjustments for body mass index. They had significantly higher LM and FM but no differences in %FM. They had significantly higher osteocalcin but lower CTx, insulin and leptin concentrations. Leptin levels were strongly correlated to %FM (r=0.85, p<0.0001), as well as to absolute FM (r=0.77, p=0.0002), in the rugbymen group. Rugby practice was associated to a bone remodelling process in favour of bone formation. There was a significant hypoleptinaemia in our rugby players, while their percent FM was equivalent and absolute FM significantly higher than the control levels. These data suggest that leptin is under control of physical activity and not just fat mass.