Calcium And Phosphorus-Metabolism In The Elderly - A Study Of 101 Institutionalized Subjects

Calcium and phosphorus metabolism was studied in 101 institutionalized subjects over 70 years of age (mean: 82.5 years). The study was performed in serum and urine; it included parathyroid hormone and calcidiol (250HD3) assays and radiological examination of bones with determination of Meunier's index and metacarpal cortical index. Calcidiol concentrations did not vary with age but were higher in people who left the institution and in men. In contrast, there was a significant age-group related increase of parathyroid hormone concentrations. This increase was accompanied by an increase of parathyroid hormone activity, as shown by a parallel fall in phosphorus reabsorption rate. These findings are in agreement with current pathogenetic theories on senile osteoporosis. Invalid subjects had higher urinary calcium and serum parathyroid hormone levels and a lower cortical index. Paradoxically, there was less vertebral collapse as evaluted by Meunier's index, which may suggest that very old patients develop progressive cortical bone hyperresorption entirely independent of sequelae from their former trabecular osteoporosis.