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A previous Derby News  article “Covid-19: Caution urged in jumping to conclusions on Black and Minority Ethnic death risks” analysed the recently published Public Health England report “Disparities in the risk and outcomes of COVID-19”. This looked at different reasons as to why people might be at higher risk of death from Covid-19.

One of these was ethnicity.

The report did not provide any direct answers as to why this might be the case, although it is possible to infer some obvious reasons from the data.  No comment was made as to whether being Black/Asian was, in itself, a contributing factor.

What do most people die of who are infected with Covid-19?

According to ‘Critical Care’ the international medical journal for people managing care for critically ill patients,

“COVID-19 is highly infectious and can lead to fatal comorbidities especially Acute Respiratory Distress Syndrome”

The May 2020 Lancet article “Intensive care management of coronavirus disease 2019 (COVID-19): challenges and recommendations”  reported that :

“Acute hypoxaemic respiratory failure— sometimes with severe hypercapnia—from acute respiratory distress syndrome (ARDS) is the most common complication (in 60–70% of patients admitted to the ICU)”

Research reported in The Journal of the American Medical Association March 2020 “Risk Factors Associated With Acute Respiratory Distress Syndrome and Death in Patients With Coronavirus Disease 2019 Pneumonia in Wuhan, China” stated that more than 40% of individuals in the study hospitalised for severe and critical COVID-19 developed ARDS—and over 50% of those diagnosed died from the disease.

ARDS happens when the lungs become severely inflamed from an infection or injury. The inflammation causes fluid from nearby blood vessels to leak into the tiny air sacs in your lungs, making breathing increasingly difficult. These are the classic symptoms of Covid-19 for those who are severely ill.

In 2017, the British Medical Journal published an article “Vitamin D supplementation to prevent acute respiratory tract infections” which concluded that, for people who were Vitamin D deficient, the numbers of severe infections were reduced by 70% if the deficiency was corrected by a daily regime of Vitamin D supplements.

Why are people deficient in Vitamin D?

Vitamin D can be found in the diet, but the majority of it is synthesised from exposure to the sun, and especially strong ultra violet (UV) light. Deficiency in this Vitamin is widespread particularly in Europe. The American Journal of Clinical Nutrition published a research paper in April 2016 “Vitamin D deficiency in Europe: pandemic?” which made a number of interesting comments and conclusions.

Its main conclusion was :

“Vitamin D deficiency is evident throughout the European population at prevalence rates that are concerning and that require action from a public health perspective. What direction these strategies take will depend on European policy but should aim to ensure vitamin D intakes that are protective against vitamin D deficiency in the majority of the European population”

It also commented:

“….suggests that vitamin D deficiency is widespread across Europe and at prevalence rates that meet the criteria of a pandemic”

“Nonwhite populations in Europe are at higher risk of vitamin D deficiency than their white counterparts. For example, compared with white populations in the United Kingdom, Norway, and Finland, the nonwhite population subgroups have 3- to 71-fold higher yearly prevalence of vitamin D deficiency.”

“….. United Kingdom… the prevalence of vitamin D deficiency was 35.7% and 59.6% in black  and Asian participants, respectively, compared with 19.6% in white participants”

Why is there such a deficiency amongst non-white people?

A June 2014 paper published in BMC Public Health “Skin pigmentation, sun exposure and vitamin D levels”, stated:

“Vitamin D synthesis is highly dependent on the concentration of melanin in the skin as melanin absorbs and scatters UVR-B… Therefore, dark-skinned individuals will experience slower vitamin D synthesis than light-skinned ones. This is especially important at higher latitudes where the incidence and duration of sunlight is reduced.”

The consequence of this is that Black/Asian people need 6 times more exposure to the sun than white people to get enough Vitamin D.

Another factor considered by the PHE report was obesity.  A report published in February 2013 by PLOS Medicine “Causal Relationship between Obesity and Vitamin D Status” concluded that a higher BMI resulted in Vitamin D deficiency.

“Population level interventions to reduce BMI are expected to decrease the prevalence of vitamin D deficiency.”

This is because  Vitamin D is fat soluble which means that it is absorbed and stored into the body fat, first, before it circulates in the blood to do its routine function.  People who are obese have to have a higher content of Vitamin D in their diet / more exposure to the sunlight, than those who are less obese.

Comment

Light-skin, in humans, was an evolutionary adaptation as people migrated out of Africa into the more northern parts of Europe. It absorbed more of the UV from the limited sunlight to generate the right levels of Vitamin D.

Nowadays, we all spend more time inside, are cautioned about the harmful effects of the sun, and apply high strength barrier creams that block out the UV light. For people with darker skin tones, they will, naturally, have progressively more of a “shield” against the sun, and a greater risk of Vitamin D deficiency.

The causal link between this deficiency and the likelihood of a severe form of respiratory infection is the subject of much high quality research, and shouldn’t be ignored. Whist Vitamin D won’t stop the initial infection it could reduce the severity, and so improve people’s chances of survival.

Perhaps Public Health England is over-analysing the problem.  Perhaps a simple recommendation for all people, but especially those with darker-toned skins, should be to take a modest, daily dose of Vitamin D supplements.  At around £15 for a year’s supply…it could help, significantly!

Postscript

In an article in Sweden’s “The Nation” from December 2018 “Swedish TV warns ‘dark-skinned’ people, Muslims of Vitamin D deficiency”

At present, there is a general recommendation to prescribe vitamin D tablets to anyone who is either dark-skinned or wearing comprehensive clothing.

But for many it would be a far too low of a dose, midwife Kristina Wally-Byström argued. Nutritionist and doctor of medical science Linda Bakkman also identified burqa-wearing dark-skinned ladies as a risk group as regards vitamin D deficiency, which may result in cancer, diabetes and cardiovascular diseases.