American Journal of Clinical Nutrition, Vol 11, 263-269, Copyright © 1962 by The American Society for Clinical Nutrition, Inc.

The Relation Between Calcium Intake and Roentgenologic Osteoporosis

¹ From the University Department of Medicine, Gardiner Institute, Western Infirmary, Glasgow, Scotland

Diet histories and x-ray scores are reported in 128 cases of osteoporosis and 103 "normal" subjects. The mean calcium and protein intakes of the "normal" subjects were significantly higher than those of the patients with osteoporosis. However, the mean calcium excretion was the same in the two groups.

Virtually no subjects on high calcium intakes were found to have osteoporosis, but low calcium intakes were frequently associated with apparently normal bones. Many of these latter subjects, however, complained of backache.

The present study sheds no light upon the role of age in the pathogenesis of osteoporosis except insofar as the duration of negative calcium balance would be a factor in determining the onset of clinical manifestations. Thus, a negative calcium balance of 100 mg. per day would involve the removal of 36.5 gm. of calcium from the skeleton every year, with a corresponding destruction of whole bone. If clinical osteoporosis involves the destruction of about 30 per cent of the skeleton then it would take about ten years for osteoporosis to develop at this rate of negative balance. A negative balance of 50 mg. per day could last for twenty years before it caused a clinical disease. In these circumstances, it is inevitable that the disease becomes more frequent with advancing age and should, in fact, appear to be a manifestation of the aging process.