[Clinical applications expected in the future--osteoporosis].

Severe vitamin deficiency causes osteomalacia, but osteoporosis is also associated with decreased vitamin D activity. Intestinal calcium absorption is decreased and vitamin D metabolites low in osteoporosis and cytokine and growth factor abnormalities in osteoporosis may be ascribed to vitamin D deficiency. In Japan, 1 alpha (OH) vitamin D3 and 1.25(OH)2 vitamin D3 have been used for osteoporosis with beneficial effect and scarcely any side effects for many years. World wide, the effect of vitamin D on osteoporosis is gradually recognized. The higher the dose, longer the duration of administration and older the age of the patients, more positive effects tend to be obtained.