Heliotherapy is superior to oral vitamin D in prevention of high blood pressure and bone health

Objective

The aim was to compare the effects of vitamin D on blood pressure and bone health after different forms of application.

Materials and methods

Sixty patients (37 male, 27 female, median age 58 years) with untreated mild essential hypertension were randomised in a prospective, single-blinded clinical trial and treated over a period of 10 weeks (January–March) twice weekly. Group 1: 30 patients were irradiated with a sun-similar UV-spectrum (UVB 3.5%) and took placebo tablets. Group 2: 34 patients were treated with 10 000 IU native vitamin D₃ and placebo (UVA) irradiation as control. 32 patients (17 Group 1 vs. 16 Group 2) were monitored without intervention for 1 year of follow-up. Before and after the intervention resp. follow-up period 24-h-ambulant blood pressure monitoring and bone mass (heel) by ultrasound were measured, blood samples were taken for 25(OH)D₃, 1,25(OH)₂-D₃, iPTH.

Statistics: Wilcoxon resp. Mann–Whitney test (P < 0.05).

Results

At baseline (January) vitamin D status was low (median: 25(OH)D₃ 66 nmol/l; 25/64 < 50 nmol/l). After intervention, 25(OH)D₃ increased significantly in both groups to 112 (UVB) resp. 108 (vit D₃) nmol/l. But only after UVB-irradiation significant changes of blood pressure [140/86 to 136/83 mmHg (UVB) vs. 143/87 to 145/88 mmHg (oral D₃)] and bone mass [Z-score: 0.5–0.8 (UVB) vs. 0.9–0.8 (oral D₃)] were observed.

Conclusion

Heliotherapy is superior to oral vitamin D in preventing the environmental lack of UVB during wintertime in northern latitudes. The beneficial systemic non-calcemic effects of vitamin D are evident only by the natural cutaneous source.