Age-associated endocrine deficiencies as potential determinants of femoral neck (type II) osteoporotic fracture occurrence in elderly men.

Osteoporotic fractures, and especially hip fractures, are a leading cause of morbidity and mortality among elderly men. Among other factors, a decline in bone mass has been identified as the major determinant of the age-related reduction in bone strength and therefore of osteoporotic fracture risk. Recent evidence suggests that age-associated endocrine deficiencies may contribute to femoral bone loss and hip fracture occurrence in elderly men. The decline in circulating androgen levels and the decreased activity of the growth hormone insulin-like growth factor-I axis may result in a reduction in bone formation that contributes to the age-related increase in bone fragility in men. Vitamin D deficiency-induced secondary hyperparathyroidism, on the other band, may further enhance bone loss by activating bone turnover and so increasing the number of bone remodelling units with impaired bone formation. On the basis of these pathophysiological models, guidelines can be developed for the prevention of age-related bone loss in men, but these approaches lack validation. The results of controlled intervention trials will have to be awaited to answer the question of whether hormone replacement therapy attenuates bone loss and reduces fracture incidence in elderly men.