Figure 1

DXR-BMD in relation to disease duration. The mean Z-score (SD) of the patients was estimated as piece-wise linear and continuous function of the disease duration. The corresponding function for the general population coincides with the x-axes. (Z-score = -0.6796 + 0.0028 min(duration, 5) - 0.4177 max(min(duration-5, 10-5), 0) -0.0209 max(duration-10, 0) (multiple correlation coefficient 0.60)).