Intended for healthcare professionals

Rapid response to:

Editor's Choice Editor’s choice

The burning building

BMJ 2020; 368 doi: (Published 19 March 2020) Cite this as: BMJ 2020;368:m1101

Rapid Response:

Inhabitants of Swedish-Somali origin are at great risk for covid-19

In Editor’s choice of 19 March Fiona Godlee writes, “With the covid-19 pandemic we have entered extraordinary times, when some things are known but many more are not and where decisions must be made nonetheless.”[1] We fully agree.

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.

Socio-economic factors, e.g. cramped housing accommodation, high rates of smoking and poor understanding of the Swedish language (which in turn leads to poor understanding of health information on covid-19 provided by the authorities) may explain the situation. Another possible explanation is Ethnic benign neutropenia - the most common form of neutropenia worldwide and very common among East African populations.[2]

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.;

1. Godlee F. The burning building. Editor’s choice. BMJ 2020;368:m110110.1136. doi: 10.1136/bmj.m1101.
2. Palmblad J, Höglund P. Ethnic benign neutropenia: A phenomenon finds an explanation. Pediatr Blood Cancer 2018;65(12):e27361. doi: 10.1002/pbc.27361.
3. Demeke T, Osmancevic A, Gillstedt M, Krogstad AL, Angesjö E, et al. Comorbidity and health-related quality of life in Somali women living in Sweden. Scand J Prim Health Care 2019;37:174-81. doi: 10.1080/02813432.2019.1608043.
4. Kalliokoski P, Bergqvist Y, Löfvander M. Physical performance and 25-hydroxyvitamin D: a cross-sectional study of pregnant Swedish and Somali immigrant women and new mothers. BMC Pregnancy Childbirth 2013;13:237. doi: 10.1186/1471-2393-13-237.
5. Cashman KD, Ritz C, Adebayo FA, Dowling KG, Itkonen ST, et al. Differences in the dietary requirement for vitamin D among Caucasian and East African women at Northern latitude. Eur J Nutr. 2019; 58:2281-91. doi: 10.1007/s00394-018-1775-1.
6. Granlund L, Ramnemark A, Andersson C, Lindkvist M, Fhärm E, Norberg M. Prevalence of vitamin D deficiency and its association with nutrition, travelling and clothing habits in an immigrant population in Northern Sweden. Eur J Clin
Nutr. 2016;70:373-9. doi: 10.1038/ejcn.2015.176.
7. Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017;356:i6583. doi: 10.1136/bmj.i6583.
8. Bergman P, Norlin AC, Hansen S, Rekha RS, Agerberth B, et al. Vitamin D3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind intervention study. BMJ Open. 2012;2(6). pii: e001663. doi: 10.1136/bmjopen-2012-001663.
9. Xu J, Yang J, Chen J, Luo Q, Zhang Q, Zhang H. Vitamin D alleviates lipopolysaccharide‑induced acute lung injury via regulation of the renin‑angiotensin system. Mol Med Rep. 2017;16:7432-8. doi: 10.3892/mmr.2017.7546.
10. Wan Y, Shang J, Graham R, Baric RS, Li F. Receptor recognition by the novel coronavirus from Wuhan: an analysis based on decade-long structural studies of SARS Coronavirus. J Virol. 2020;94(7). doi: 10.1128/JVI.00127-20.

Competing interests: No competing interests

24 March 2020
Susanne Bejerot
Professor, MD
Mats Humble, MD, PhD
Örebro University, School of Medical Sciences
Campus USÖ, SE-70182 Örebro, Sweden