Estimation of the bone mineral density variation associated with changes in turnover rate

Bone matrix mineral density (BMDn, fraction of maximum) is the mean mineral density of a bone sample comprising moieties of bone of varying ages/mineral densities. A method for calculating BMDn as a function of bone turnover rate is presented. The method is based on a mineralization curve defined by values for mineralization lag time, total mineralization time, and levels of primary and final mineralization. The calculations illustrate that BMDn decreases linearly in direct proportion to increases in bone turnover rate, and that the slope of the line is dependent on the assumptions used to calculate the mineralization curve. BMDn variation is important because it is reflected in whole bone density variation, independent of changes in bone mass, when bone turnover rate is altered.