Abstract
Calcium absorption was measured by plasma radioactivity after oral calcium isotopes in seventy-five men and one hundred and fifteen women aged 20-95 years. Absorption of calcium fell with age after about 60 years and everyone over 80 had significant malabsorption. This malabsorption of calcium in the elderly may well be due to vitamin-D deficiency, and could play a significant role in the pathogenesis of fractures in old people.