Clinical and biochemical study of senile osteoporosis: Significance of the calcitonin load test

Serum levels of calcium and phosphorus and total urinary hydroxyproline excretion were determined in 30 elderly persons over 65 years of age who had primary hyperalkalinephos-phatasemia and clear osteoporotic changes in their lumbar spinal column. The clinical and biochemical status of individual patients was compared. The total urinary hydorxyproline excretion was 7.75mg/day to 32.29mg/day (mean: 15.11±7.19mg/day by patient with gait activity and 16.95mg/day to 35.00mg/day (mean: 24.08±6.86mg/day) by patient without gait activity. The lower total urinary hydroxyproline excretion by patients with gait activity than by patients without gait ativity suggested lower bone turnover in the former. In 20 out of these 30 elderly patients, 80 I.U. of porcine calcitonin was injected intramuscularly, and changes in serum calcium and phosphorus levels and total urinary hydroxyproline excretion were observed. This test revealed no correlation between the observed changes and the grade of gait activity of severity of osteoporotic bone changes. The serum calcium level decreased significantly from 4.2mEq/L to 5.3mEq/L (mean: 4.67±0.37mEq/L) before the load test to 4.0mEq/L to 5.0mEq/L (mean: 4.35±0.27mEq/L) after the test in 10 patients. It is postulated that in these 10 patients osteoclastic activity was higher with greater resorption of bone as compared to patients in whom no decrease in the serum calcium level was induced by the carcitonin load test.