Vitamin D deficiency in Ireland
Implications for COVID-19.

Published by Eamon Laird & Rose Anne Kenny
The Irish Longitudinal Study on Ageing. On behalf of the TILDA team (April 2020)

Results from the Irish Longitudinal Study on Ageing (TILDA)

This report demonstrates that of those aged 55+ years in Rep. of Ireland, 1 in 5 are vitamin D deficient during the winter and 1 in 12 during the summer. Of particular concern is that nearly 30% of those aged 70+ and 47% of those aged 85+ are deficient in vitamin D. These are the age groups who are considered to be ‘extremely medically vulnerable’ to the adverse health outcomes of COVID-19 and have been advised to participate in ‘cocooning’ during the COVID-19 public health emergency. Of extra concern is the fact that only 10.5% of those aged 70+ actually report taking a vitamin D supplement – because of ‘cocooning’ many may now lack the opportunity for sun exposure and given the low use of supplements, many of this vulnerable group could be at very high risk of deficiency. This of key importance given the usefulness of vitamin D for immune function particularly at this time.

Of particular concern we have observed very high levels of vitamin D deficiency in those who are obese and those with pre-existing lung conditions both of which have been observed to make individuals particularly vulnerable to COVID-19 and complications from the virus (15,16).

Ireland does not have any formal vitamin D food policy – we practice a voluntary but not mandatory food fortification policy where food manufacturers can decide to fortify (or not) their food products with vitamin D. The vitamin D status of those in Ireland is lower than either the United States or Canada who have systematic (mass) vitamin D food fortification. However, vitamin D deficiency is not inevitable in older adults in Ireland and the ability to have sufficient vitamin D status year round is an achievable goal that many countries meet. For example, another European country – Finland (which is at a much higher latitude and therefore receives less sunshine than Ireland) has virtually eliminated vitamin D deficiency in its population with rates <1% (17). This is due in part to a successful food fortification and vitamin D supplement policy and educating the public and medical practitioners on the importance of vitamin D. This vitamin D success story demonstrates what could be achieved in Ireland.

Key Messages

Why is Vitamin D important?
• Vitamin D is essential for bone and muscle health
• Vitamin D may help prevent respiratory infections in those who have low vitamin D
levels
• Vitamin D is seasonal and cannot be made during the winter-time while the amount in
summer time is subject to sunshine, weather and other factors

What are the rates of deficiency in older adults in Ireland*?
• 47% of all adults aged >85 are deficient in winter (31,480)
• 27% of the over 70s who are ‘cocooning’ are likely to be deficient (115,536)
• 1 in 8 (13%) adults over 55 are deficient (149,049) all year

Who is at risk of Vitamin D deficiency in Ireland?
• People who are housebound/confined, little sun exposure and/or eat inadequate
amounts of fortified foods
• People who don’t take vitamin D supplements – currently over 91% of older adults 55+
do not take a supplement during the winter (1,038,752). Only 4% of men and 15% of
women take a supplement
• People who are obese, physically inactive, have asthma or chronic lung disease

• Where is vitamin D found
  • Vitamin D is made in the skin from 10-15 minutes per day of sun exposure – in Ireland
  only made from late March to late September
  • Vitamin D is available in oily fish (salmon, mackerel etc.), eggs, liver, fortified foods
  such as cereals and dairy products

Conclusion

Our people aged 70 and over are the fabric of our society (19) and we must use all available tools to facilitate the reduction and transmission of COVD-19. Vitamin D is a potent immune modifying micronutrient and if vitamin D status is sufficient, it could benefit vulnerable adults in particular those 70+ years and older who are ‘cocooning’ during the COVID-19 outbreak.

Read the full report

For further information see: Laird E, O’Halloran AM, Carey D, Healy M, O’Connor D, Moore P, Shannon T, Molloy AM, Kenny RA. The prevalence of vitamin D deficiency and the determinants of 25 (OH)D concentration in older Irish adults: Data from The Irish Longitudinal Study on Ageing (TILDA). The Journals of Gerontology: Series A. 2018 73(4):519-525. https://academic.oup.com/biomedgerontology/article/73/4/519/4103040