Ultraviolet irradiation corrects vitamin D deficiency and suppresses secondary hyperparathyroidism in the elderly

The objective of this study was to compare the effect of ultraviolet radiation (UV) and oral vitamin D-3 on the vitamin D status and parathyroid hormone (PTH) concentration in elderly nursing home patients. The design of the study was a randomized clinical trial, The setting mas a psychogeriatric nursing home. Subjects included 45 female psychogeriatric patients with a mean age of 85 years. Exclusion criteria were going outdoors more than once a week and the presence of actinic or cancer skin lesions, Intervention was random allocation of W-B irradiation at half the minimal erythemal dose of the lower back, three times per week during 12 weeks (W-B), or oral vitamin D-3 400 IU/day during 12 weeks (VIT-D), or no treatment (CONTR), Main outcome measures were change in fasting serum levels of vitamin D metabolites at 0, 2, 4, 8, and 12 weeks in the treatment groups, compared with the control group. PTH(1-84) was measured at 0 and 12 weeks, Baseline serum 25-hydroxyvitamin D (25(OH)D) was lower than 30 nmol/l in 95% of the participants. It increased to a median value of around 60 nmol/l after 12 weeks both in the UV-B and VIT-D groups, whereas there was no change in the CONTR group. Serum 1,25-dihydroxyvitamin D increased significantly in the UV-B group, Serum calcium increased significantly in both treatment groups. Serum PTH decreased more than 30% in both treatment groups (p < 0.001), whereas there was no significant change in the control group. Irradiation with W-B in the very elderly for a few minutes per day leads to adequate improvement of the vitamin D status. It is as effective as oral vitamin D-3 in increasing serum 25(OH)D and suppressing secondary hyperparathyroidism.