Vitamin D is a hormone produced in the skin via a non-enzymatic process involving ultraviolet light.It is well known that the physiology of aging makes older people particularly susceptible to... Show moreVitamin D is a hormone produced in the skin via a non-enzymatic process involving ultraviolet light.It is well known that the physiology of aging makes older people particularly susceptible to vitamin D deficiency and that, if untreated, it can have serious health consequences. This thesis deliberates on the topics of vitamin D supplementation in older people in light of the current guidelines and on the possible additional effects of ultraviolet light beyond vitamin D synthesis on nursing home residents. We present a cross-sectional study in nursing home residents aged 70 years and over designed to evaluate the efficacy of vitamin D supplementation in achieving vitamin D sufficiency. We also discuss the different supplementation strategies for nursing home residents and community dwelling persons aged 70 years and over based on a survey administered to general practitioners and elderly care physicians in the Netherlands.In the second part we concentrate on additional effects of ultraviolet light beyond vitamin D synthesis. We describe our systematic review of literature on the effect of ultraviolet light, when applied to the skin or eyes, on mood, depression and well-being. We present also our randomized controlled trial on the effect of ultraviolet radiation compared with oral vitamin D supplementation on the well-being of nursing home residents with dementia. Further we use the data of the RCT to carry out a post-hoc analysis to compare the effect of vitamin D alone compared with ultraviolet radiation on the blood pressure of old people with dementia. Show less
The overriding aim of my thesis was to study the relationship between blood pressure (BP) and cognitive and psychological functioning in older persons. Observational studies indicate that lower BP... Show moreThe overriding aim of my thesis was to study the relationship between blood pressure (BP) and cognitive and psychological functioning in older persons. Observational studies indicate that lower BP increases risk for cognitive decline in older persons. Older persons are at risk for impaired cerebral autoregulation, and lowering their BP may compromise cerebral blood flow and cognitive function. Contradictory to our hypothesis, the Discontinuation of Antihypertensive Treatment in Elderly people (DANTE) Study Leiden, a community-based randomized clinical trial in older persons (aged ≥75 years) with mild cognitive deficits, did not show that discontinuation of antihypertensive treatment improves cognitive functioning. The lack of the effect of this trial may be due to the unintentional inclusion of persons with a relatively intact cerebral autoregulation. Furthermore, we demonstrated that older persons with mild cognitive deficits and with orthostatic hypotension, who discontinued all their antihypertensive medication had an increased probability of being free from orthostatic hypotension 4 months later, compared to persons who continued their medication. Finally, in the DANTE MRI sub study, the relationship between BP and both conventional features of small vessel disease (SVD) and microstructural damage was explored, as well as the relation between microstructural damage and cognitive and psychological dysfunction. Show less
