[Study of vitamin D deficiencies in the aged].

Plasma levels of 25-hydroxycalciferol (25-OH-D) and the biological parameters of phosphocalcium metabolism were determined in 55 patients institutionalized in a geriatric hospital in Geneva. They were compared with two control groups, one of the same age and the other younger. The mean plasma 25-OH-D level of the hospitalized patients was 22.