Over a quarter of adults aged 50+ are deficient in vitamin D according to researchers from Trinity College Dublin who announced their findings today (Thursday, June 13th). Over half (57%) had inadequate serum vitamin D levels, of which 26% were classed as vitamin D deficient. Vitamin D has a known role in bone health, with growing evidence for beneficial effects on muscle strength and other non-skeletal outcomes. The study was recently published in the international, peer-reviewed journal Nutrients.
Better understanding of factors that contribute to vitamin D deficiency is needed to identify people most at-risk. Determinants of deficiency identified in this new study were female gender, advanced age (80+ years), smoking, non-white ethnicity, obesity and poor self-reported health. Researchers therefore identified a profile of older people more likely to be at risk of vitamin D deficiency. Being of a healthy weight, retired, engaging in regular vigorous physical activity, vitamin D supplement use, sun travel in past 12 months and summer season were positive determinants, and therefore potentially protective factors against vitamin D deficiency in older people.
The findings were based on 6004 midlife and older adults, living at Northern latitudes (England, 50-55oN) derived from the English Longitudinal Study of Ageing (ELSA). Since UVB radiation (sunlight) is a known determinant of vitamin D status, this was investigated. Interestingly, residents in the South of England had a reduced risk of deficiency, compared with the North, even after adjustment for socioeconomic and other predictors of vitamin D status.
This new research demonstrates that vitamin D deficiency is prevalent in older adult populations living at Northern latitudes and highlights the importance of public health strategies throughout midlife and older age to achieve optimal vitamin D status.
Associate Professor in Nutrition at Trinity College, Maria O'Sullivan commented 'Our study identified factors associated with vitamin D deficiency, including being aged 80+ years, obesity and sedentary lifestyles; all of which are increasing traits in western populations. Furthermore, this is one of the few studies to highlight the importance of non-white ethnicity in vitamin D deficiency in a large study of aging. The findings are valuable in developing targeted strategies to eliminate vitamin D deficiency (at 30nmol/L) in older populations'.
First Author Dr Niamh Aspell, who conducted the study as part of her PhD at Trinity said:
Those who used a vitamin D supplement, were less likely to be vitamin D deficient as may be expected, but supplement use was low (4.4%) and, therefore, food fortification and other strategies need to be considered at policy level for older populations."
Co-Author and Trinity Research Fellow Dr Eamon Laird, said:
The high rates of deficiency are similar to rates seen in other high latitude countries such as Ireland. However, other more northern countries such as Finland have implemented a successful vitamin D fortification policy which has all but eliminated deficiency in the population. Such a policy could easily be implemented in the UK and Ireland."
Trinity College Dublin
Aspell, N. et al. (2019) The Prevalence and Determinants of Vitamin D Status in Community-Dwelling Older Adults: Results from the English Longitudinal Study of Ageing (ELSA). Nutrients. doi.org/10.3390/nu11061253.