In response to the COVID-19 pandemic, The Irish Longitudinal Study on Ageing (TILDA) research teams have reoriented their work to assist the planners and providers of health services in Ireland in managing the crisis.
Dr Eamon Laird and Prof Rose Anne Kenny, from the School of Medicine at Trinity College Dublin and part of the TILDA team, alongside Professor Jon Rhodes at University of Liverpool, analysed all European adult population studies, completed since 1999, which measured vitamin D and all that compared vitamin D with death rates from COVID-19.
In their report, published in the Irish Medical Journal, they point out that vitamin D can support the immune system through a number of immune pathways involved in fighting SARS2COV and many recent studies confirm the pivotal role of vitamin D in viral infections.
This study shows that, counter intuitively, countries at lower latitude and typically sunny countries, such as Spain and Northern Italy, had low concentrations of vitamin D and high rates of vitamin D deficiency. These countries also experienced the highest infection and death rates in Europe.
The northern latitude countries of Norway, Finland and Sweden, have higher vitamin D levels despite less UVB sunlight exposure, because supplementation and fortification of foods is more common. These Nordic countries have lower COVID-19 infection and death rates. The correlation between low vitamin D levels and death from COVID-19 is statistically significant.
The authors propose that it is also likely that vitamin D supplementation will reduce serious COVID-19 complications. This may be because vitamin D is important in regulation and suppression of the inflammatory cytokine response, which causes the severe consequences of COVID-19 and 'acute respiratory distress syndrome' associated with ventilation and death.
Prof Kenny said deficiency is prevalent in Ireland and the government needs to change its recommendations in line with the rest of the UK.
"In England, Scotland and Wales, public health bodies have revised recommendations since the COVID-19 outbreak. Recommendations now state that all adults should take at least 400 IU vitamin D daily.
"Whereas there are currently no results from randomised controlled trials to conclusively prove that vitamin D beneficially affects COVID-19 outcomes, there is strong circumstantial evidence of associations between vitamin D and the severity of COVID-19 responses, including death.
"This study further confirms this association. We call on the Irish government to update guidelines as a matter of urgency and encourage all adults to take supplements during the COVID-19 crisis. Deficiency is frequent in Ireland. Deficiency is most prevalent with age, obesity, in men, in ethnic minorities, in people with diabetes, hypertension and in nursing homes."
Dr Laird added: "Here we see observational evidence of a link of vitamin D with mortality. Optimising vitamin D intake to public health guidelines will certainly have benefits for overall health and support immune function.
"Research like this is still exploratory and we need further trials to have concrete evidence on the level of vitamin D that is needed for optimal immune function.
"However, studies like this also remind us how low our vitamin D status is in the population (even in sunny countries) and adds further weight to some sort of mandatory vitamin D fortification policy. If the Nordic countries are allowed to do this, there is no reason Ireland, the UK or rest of Europe can't either."
The Irish Longitudinal Study on Ageing (TILDA)
The TILDA dataset represents an unparalleled resource for understanding the health, social and economic situation of the older population in Ireland, among which are some of the most vulnerable in this crisis.
TILDA researchers have been redeployed to expedite analysis of its Wave 5 data (2018) to provide national estimates of the prevalence of factors relevant to response planning, including: those living alone; those who are frail or pre-frail; the prevalence of a variety of chronic conditions and disabilities; the numbers taking different types of medications; the numbers providing essential family care to a relative; and healthcare utilisation including home help and other HSE services. See TILDA Report to Inform Demographics for Over 50s in Ireland for COVID-19 Crisis
Source: Irish Medical Journal
Laird. E., et al
"Vitamin D and inflammation: Potential implications for severity of Covid-19"