Ultra-violet irradiation and 25-hydroxy-vitamin D levels in sick old people.

Twelve elderly patients in a rehabilitation ward were given a four-week course of ultra-violet irradiation from a Vitalux lamp. They were compared with 12 controls selected from the same ward. Treatment produced a significant elevation in plasma 25-hydroxy-vitamin D (25OHD) by the end of the second week and concentrations continued to rise over the four-week period. Subject showing the greatest response were those starting with the lowest levels of plasma 25OHD. The findings suggest that ultra-violet irradiation is an effective means of treating vitamin D deficiency in old age and that patients with the greatest degree of deficiency show the greatest response.