The vitamin D metabolites in the pathogenesis and management of osteoporosis.

Studies on post-menopausal osteoporotic patients indicate that 1,25-(OH)2 D3 concentrations are no different from those in age-matched normal subjects and the data suggest that the malabsorption of calcium found in many osteoporotic patients cannot generally be attributed to low plasma 1,25-(OH)2 D3 levels. The effects are discussed of three different therapies - sex hormones alone, vitamin D metabolites alone and a combination of both - on calcium balance and peripheral bone loss in treated compared with untreated osteoporotic patients. The results indicate that combined therapy with a vitamin D metabolite and an oestrogen is more effective in inhibiting the rate of bone resorption in post-menopausal osteoporosis than treatment with either agent used alone, and should be regarded as the treatment of choice at the present time. It is suggested that, using this regimen which is suitable for patients up to about 65 years of age, calcium supplementation is not required, provided daily calcium intake is reasonably adequate, and may even be undesirable by increasing the risk of hypercalcaemia.