SIR—Bone loss, the major determinant of hip fracture risk in the elderly [1], results from an increased rate of bone turnover [2] that will amplify the imbalance at the level of the individual remodelling unit. However, while the increase in bone turnover in elderly women results in part from secondary hyperparathyroidism [3], the mechanisms responsible for the age-related decline in bone formation have not yet been identified.
Read full abstract