Abstract
To investigate the tendency of change of Bone mineral density (BMD) with age is important to seek Peak bone mass. Many cross-sectional studies have been carried out examining the change of BMD with age. Few cross-sectional studies were reported statistically the tendency of change of BMD with age. We applied speed of sound (SOS) for indicator to examine BMD. In this study, we measured SOS in 145 healthy Japanese women aged 20-49. We examined the tendency of change of SOS with age based on least square approximation polynomial. To determine the best least square approximation polynomial, we compared each coefficients of determination and sum of residual square. Finally the best least square approximation polynomial was cubic least square approximation polynomial. We proposed the standard change chart of SOS value with age based on the cubic least square approximation polynomial. In future studies, examining the change of SOS with age based on more data is needed because of the reliability.
