Among the first 15 deaths due to covid-19 in Stockholm County, six were reported, by the Swedish-Somali medical society, to be of Somali origin (March 24). Considering that only 0.84% of the Stockholm County population was born in Somalia (n=8,178 by December 2019) this is an astonishing high rate.
A risk factor that we want to highlight, however, is the low vitamin D levels found in the Swedish-Somali population. Vitamin D status is strongly related to low sun exposure and dark skin. In two different studies, the great majority of Swedish women of Somali origin had very low levels of S-25(OH)-D (< 25 nmol/l).[3,4] In Finland, Somali women required more than twice the amount of vitamin D in order to maintain recommended vitamin D status. [5] In addition, vitamin D deficiency was twice as common, regardless of gender, in immigrants from Africa compared with those from the Middle East.[6]
There is evidence that vitamin D is involved in our defence against respiratory tract infections. According to a meta-analysis, vitamin D supplementation (daily-weekly dosage) prevents acute respiratory tract infections, especially in those with 25(OH)-D below 25 nmol/l (NNT = 4).[7] In a randomised trial on individuals with frequent respiratory tract infections, treatment with cholecalciferol 4000 IE/day reduced the need for antibiotic treatment.[8] The mechanism is debated; however, modulation of the renin-angiotensin system has been implicated in animal studies of acute respiratory distress syndrome,[9] and angiotensin-converting enzyme 2 is a well-established receptor for the SARS-CoV virus.[10]
In order to cope with the covid-19 epidemic, preventive measures could be administration of vitamin D to high-risk populations, e.g. dark-skinned adults with low sun-exposure and/or individuals with risk factors for respiratory tract infections. Although it may not always be helpful, it is unlikely to be harmful.
https://www.bmj.com/content/368/bmj.m1101/rr-10