Influence of mechanical loading and skeleton geometry in bone mass at the proximal femur in 10[ndash]12 years old children: a longitudinal study

Abstract

BPAQ was a significant positive predictor for all BMD variables (p<0.05) except TR BMD in girls and FN BMDs in boys (>0.05).  At least one geometric variable was significant in the estimated models for the BMD ratios: in girls, the IAD was a positive predictor of TR:PF (p<0.001) and ALA was a negative predictor of FN:PF; in boys, the IAD was a positive predictor of FN:PF (p<0.01) and IM:SL (p<0.05); also in boys, ALA was a negative predictor of the IM:SL (p< 0.001).  The interaction of IAD*ALA predicted IM:SL positively in girls and negatively in boys (p<0.01).  The IAD and the ALA, as indicators of the main lever arms of the biomechanics of the hip, may play a role in the relative mineralization of the proximal femur in peripubertal boys and girls, as was theoretically expected..  However unlike total lean body mass and PA, the same geometric variables don't seem to influence the absolute BMD levels at the proximal femur neck and trochanter..  Further research is needed to better understand the effects of geometric variables on the relative mineralization of the proximal femur regions including the development of a specific biomechanical model to simulate the vector forces exerted on these regions.