Fifteen years after their forearm bone mineral content was measured, 366 women were measured again with the same single photon technique. 96 of the women had sustained one or more fragility fractures during that period. The initial bone mineral content was less in those women who were to have fractures. The rate of loss over the years did not differ between fracture and non-fracture women—the initial bone mass was the better predictor. Peak bone mass in the women in this study occurred before the age of 40.