Rates of growth and loss of bone mineral in the spine and femoral neck in white females

This study characterizes the rates of growth and loss of bone mass as a fun ction of age in white females. It combines longitudinal data from several s tudies of bone mass on healthy white female subjects ranging from age 6 to 90 years. Rates of change in bone area, bone mineral content (BMC) and bone mineral density (BMD) are estimated separately for the spine and the femor al neck of each individual using linear regression. The individual rates of change are then fitted as a nonparametric function of age using weighted m oving averages, resulting in a curve of age-specific mean change as a funct ion of age. When the curves of BMD were compared between the hip and the fe moral neck, the cessation of bone growth and the onset of bone loss were fo und to occur at an earlier age at the hip than at the spine. No significant differences in the ages of maximum rates of growth or maximum loss were fo und between the two skeletal sites. This information will be useful for des igning interventions to promote bone growth or retard bone loss.