AbstractVitamin D is a secosteriod hormone with a key role in increasing the intestinal absorption of calcium and plays a key role in bone metabolism. Older adults, in particular those residing in care homes, are susceptible to vitamin D deficiency owing to lack of sunlight exposure, poor dietary intake of vitamin D, medication use, compromised renal function and lack of supplementation. The overall aims of this thesis were to determine, for the first time, the vitamin D status and prevalence of vitamin D deficiency in care home residents in Northern Ireland (NI), investigate factors which impact vitamin D status and to determine the association between vitamin D, musculoskeletal health outcomes and inflammatory cytokines. Dietary contribution of vitamin D and other nutrients important for bone health was investigated within care home menus in NI. Additionally, given recent evidence highlighting a role for n-3 long chain polyunsaturated fatty acids (LCPUFA) in benefiting bone heath, an investigation into the associations of long chain polyunsaturated fatty acids with bone mineral density and bone turnover markers in postmenopausal women was completed.
An extensive critical review of the literature on the vitamin D status of older adults in care homes across the globe outlined a high prevalence of vitamin D deficiency and identified that those residents that were severely deficient, deficient or insufficient require remedial supplementation prior to maintenance supplementation to improve vitamin D status. In addition, promising findings in relation to intervening with vitamin D and calcium fortified foods for resultant benefits to health outcomes in care home residents were summarized identifying that more research is required in this area.
An observational study in care home residents in NI identified vitamin D deficiency and insufficiency in 34.8% and 17.4% of residents. 25-hydroxyvitamin D (25(OH)D) concentration was not an independent predictor of T-score, muscle strength, timed up and go (TUG) or inflammatory cytokines albeit, higher 25(OH)D concentration was associated with lower bone turnover. Vitamin D ± calcium supplementation was a significant predictor of a higher 25(OH)D concentration albeit many residents were not taking any form of vitamin D supplementation. Building on this, nutrient contribution of care home menus in NI identified low dietary contribution of vitamin D (3.7μg vitamin D/day) and that the inclusion of vitamin D fortified milk would increase intakes by 40.5%. Secondary analysis of a well-defined cohort of postmenopausal women, a vulnerable group also at risk of osteoporosis similarly to care home residents, showed that a low n-6:n-3 ratio was associated with higher femur bone mineral density (BMD) and a higher n-3 LCPUFA (ALA) was associated with lower bone resorption.
In this thesis, the benefit of both vitamin D and n-3 LCPUFA for the prevention of bone loss in care home residents and postmenopausal women has been demonstrated, thus the introduction of fortified milk or rich dietary sources of vitamin D and n-3 LCPUFA could be a protentional intervention to improve dietary intake of vitamin D in these groups. In addition, mandatory vitamin D ± calcium supplementation for care home residents within NI may be required to ensure vitamin D deficient residents reach sufficiency.
|Date of Award||Nov 2021|
|Sponsors||Department for the Economy|
|Supervisor||Kirsty Pourshahidi (Supervisor), Emeir Mc Sorley (Supervisor), Pamela Magee (Supervisor) & David J. Armstrong (Supervisor)|
- Vitamin D
- Bone health
- Musculoskeletal health
- Older adults
- Care home