Can we stop bone loss and prevent hip fractures in the elderly?
The two main determinants of hip fractures are falls and bone loss leading to an intrinsic femoral fragility. Substantial femoral bone loss continues throughout old age, with a continuous and exponential increase in the risk of hip fracture; thus any reduction or arrest of this loss will induce an important reduction in the incidence of hip fracture. Preventive measures may be achieved during childhood by increasing peak bone mass with calcium and exercise, by using long-term estrogen replacement therapy after menopause, but also by using vitamin D and calcium supplements for late prevention in the elderly. Vitamin D insufficiency and a deficit in calcium intake are very common in the elderly living either in institutions or at home and the cumulative response to these deficits is a negative calcium balance which stimulates parathyroid hormone secretion. This senile secondary hyperparathyroidism is one of the determinants of femoral bone loss and can be reversed by calcium and vitamin D supplements. We have shown in a 3-year controlled prospective study that the daily use of supplements (1.2 g calcium and 800 IU vitamin D3) given in a large population of 3270 elderly ambulatory women living in nursing homes reduced the number of hip fractures by 23% (intention-to-treat analysis). In parallel, serum parathyroid hormone concentrations were reduced by 28% and low baseline serum 25-hydroxy vitamin D concentration returned to normal values. After 18 months of treatment the bone density of the total proximal femoral region had increased by 2.7% in the vitamin D3-calcium group and decreased by 4.6% in the placebo group (p<0.001). This prevention is safe and can be recommended for people living in institutions. It could also be useful in other elderly subjects at particular risk due to a low calcium intake, an absence of solar exposure, a low femoral bone density, a high serum parathyroid hormone concentration, a low serum 25-hydroxyvitamin D concentration and a previous history of falls. Prospective studies are needed for further evaluation of these risk factors.