[comparison of the effects on phosphocalcic metabolism and bone of 3 protocols of vitamin D administration in the elderly]. / Comparaisons des effets sur le métabolisme phosphocalcique et sur l'os de trois protocoles d'administration pendant un an de la vitamine D chez la personne âgée.

According to recent studies, vitamin D deficiency may contribute to the osteoporosis observed in elderly subjects, with reduced intestinal calcium absorption and secondary hyperparathyroidism. Vitamin D deficiency is often present in elderly people, due to inadequate diet and confinement at home. The administration of either oral vitamin D in doses of 4,000 IU per day, or six-monthly intramuscular injections of ergocalciferol 600,000 IU, combined with a daily intake of at least 1 g of calcium brings back to normal both 25 OH D concentrations and parathyroid hormone levels. When pursued for one year, these treatments also maintain the formation of cortical bone, as shown by the metacarpal index. As for the concentration of 25 OH D, it seems that 60 to 75 nmol/l are necessary to restore calcium homeostasis. The dietary habits of elderly people are such that a supplement of medicinal calcium is required. Finally, we regard the parenteral form of ergocalciferol as being preferable to the oral form at that age for better compliance with treatment.