Vit D-UVB study

The effect of ultraviolet B irradiation compared with oral vitamin D supplementation on the well-being of nursing home residents with dementia: A randomized controlled trial

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Brief description

A multicenter randomized controlled trial which compares the effect of vitamin D supplementation versus ultraviolet light irradiation.


Prof. Dr. Mattijs Numans, LUMC
Dr. Victor Chel, head of elderly care physician specialism
Monique Caljouw, assistant professor, LUMC
Jenny van der Steen, senior researcher, LUMC
Bistra Veleva, PhD student, LUMC


Bistra Veleva, PhD student, LUMC

Participating organizations

WoonZorgcentra Haaglangen (WZH), Topaz                     

Start study

October 2016    

Expected completion

November 2021 


We conducted a randomized controlled multicentre trial to compare the effects of UVB light and vitamin D supplementation (VD) in terms of well-being of nursing home residents with dementia. Participants were randomly assigned to the intervention group (UVB group, n = 41; half-body UVB irradiation, twice weekly over 6 months, with 1 standard erythema dose (SED)) or to the control group (VD group, n = 37; 5600 International units (IU) cholecalciferol supplementation once a week). The main outcome was well-being, measured by the Cohen-Mansfield Agitation Inventory (CMAI) and the Cornell scale for depression in dementia at 0, 3, and 6 months. Secondary outcomes were QUALIDEM quality of life domains and biochemical parameters of bone homeostasis. Intention-to-treat analysis with linear mixed modelling showed no significant between-group differences on agitation (p = 0.431) or depressive symptoms (p = 0.982).

In collaboration with

SEFAS (Centre for Elderly Care and Nursing Home Medicine, Bergen Norway)


WoonZorgcentra Haaglanden (WZH)
VDL Hapro, Kapelle


Veleva BI, Caljouw MAA, van der Steen JT, Mertens BJA, Chel VGM, Numans ME. The Effect of Ultraviolet B Irridiation Compared with Oral Vitamin D Supplementation on the Well-being of Nursing Home Residents with Dementia: A Randomized Controlled Trial. Int J Environ Res Public Health. 2020;17(5)