Effects of serum calcium and several factors of bone metabolism on the bone stiffness of healthy female college students

Abstract

Ultrasound bone densitometry of os calcis was performed on a sample of three-hundred and eighty-four healthy female students. From the results, they were separated into two groups from the original samples: Group 1 (62 subjects) having over the mean stiffness value lSD+ and Group 2 (57 subjects) under the mean stiffness value lSD-.

Next, we studied the following aspects of the two groups: 1) bone mineral density of the lumber vertebrae (L₂-L₄) by dual energy X-ray absorptiometry method, 2) serum calcium and alkaliphosphatase (ALP), 3) physical characteristics (height, weight, lean body mass; LBM, %Fat), 4) calcium intake from the milk and the milk products per day.

Results were as follows: Positive correlations existed between height and the serum ALP (r = 0.350, p<0.05), and the serum calcium and the ALP (r = 0.353, p<0.05) in the Group 1. Moreover, in the group of mean stiffness value 2SD+, there was also a positive correlation between the serum calcium and the ALP (r =0.697, p<0.05). Each physical characteristic had a positive correlation to stiffness, and weight and LBM showed especially high correlation efficients.

The above mentioned results may lead the following conclusions; Taller subjects show a higher rate of bone metabolism as do those with higher levels of serum calcium. However, this is only the case with students whose bones are well developed. Heavier subjects have a higher degree of stiffness and this increases with physical development.