The effect of taking calcium and vitamin D supplements was measured using Quantitative Computed Tomography (QCT) to calculate a QTC Z score. A standardized Z-score was calculated to indicate the difference between the patient's Bone Mineral Density (BMD) and the mean value for age and gender-appropriate controls. Z-scores from 0 to +2 are considered normal, above +2 are considered to be elevated, from 0 to -1 are considered to represent a mild BMD deficit, between -1 and -2 are considered to represent moderate deficits, and below -2 are considered to represent severe deficits.