Is there a link between the disproportionate incidence and severity of COVID-19 in African Americans and vitamin D insufficiency?
Beth Ellen DiLuglio, MS, RDN, LDN
By the 20th of April 2020, over 2.5 million worldwide cases of coronavirus disease 2019 (COVID-19) had been attributed to the novel severe acute respiratory syndrome coronavirus 2 (SARS-Co-V-2). Characteristics of the disease were recognized in December of 2019 and a global pandemic was declared in March 2020.[1] As of June 14, 2020 7.98 million cases and 434,980 deaths have been reported worldwide.[2]
African Americans have been disproportionately affected by COVID-19 and have seen a six-fold increase in death rate from this grievous disease.[3] In Chicago alone, more than 50% of COVID-19 cases, and 70% of related deaths occurred in African Americans, an ethnic group also at greater risk of vitamin D deficiency. Insufficiency of vitamin D translates into a critical insufficiency of its most vital benefits including immunomodulatory, antioxidant, and anti-inflammatory properties, setting the stage for infectious disease.[4]
Vitamin D has a protective effect against respiratory tract infection, including acute viral infection. This protection increases significantly with daily or weekly supplementation, especially in those who are vitamin D deficient, an effect confirmed by meta-analysis.[5] [6] [7]
Vitamin D can be produced in the body from a cholesterol precursor in the skin in the presence of adequate UVB light from the sun. However, melanin in the skin reduces UV light absorption which in turn reduces vitamin D production.[8] Sunlight exposure may need to be five times greater in those with dark skin in order to stimulate synthesis of vitamin D. Preliminary research indicates that in areas of low solar irradiance and less sun exposure (e.g. Michigan), African American COVID-19 deaths were 193% higher than the general African American population. In areas of increased irradiance such as Florida, COVID-19 deaths in African Americans were only 7% higher than those the general African American population.[9]
Researchers are recognizing a prevalence of vitamin D insufficiency (VDI) in those with severe COVID-19 and acknowledge the presence of VDI in 80-90% of African Americans. In a pre-peer reviewed publication, researchers observed that all 11 African American ICU COVID-19 patients had vitamin D insufficiency, defined as a serum level less than 30 ng/mL (75 nmol/L). Of the 11 patients, seven had vitamin D levels less than 20 ng/mL (50 nmol/L) and three had levels less than 10 ng/mL (25 nmol/L).[10]
Interestingly, when cut-off values for vitamin D deficiency were defined as less than 10 ng/dL (25 nmol/L) and values for vitamin D insufficiency were defined as 20 ng/dL (50 nmol/L) an association between vitamin D and COVID-19 was observed but that association abated with adjustment of cofounders.[11]
Researchers recommend assessing serum vitamin D levels (25-OH vitamin D) in all COVID-19 patients and supplement as needed to achieve optimal serum levels of 40-60 ng/mL (100-150 nmol/L). Supplementation with at least 6000 IU per day may be needed to achieve serum levels of 40 ng/mL (100 nmol/L).[12]
Maintenance doses between 1000 IU (25 ug) – 10,000 IU (250 ug) per day may be needed depending on sunlight exposure, skin pigmentation, and serum levels.[13]
In conclusion, we are observing a disproportionate severity and mortality of COVID-19 in our African American community. What if something as simple as vitamin D assessment, monitoring, and repletion could help to reduce this disparity? How can we not turn over every possible stone to help provide some respite and relief to a community ravaged by this disease?
References
[1] Acter, Thamina et al. “Evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as coronavirus disease 2019 (COVID-19) pandemic: A global health emergency.” The Science of the total environment vol. 730 (2020): 138996. [R]
[2] Worldometers.info COVID-19 Coronavirus Pandemic. [R]
[3] Yancy, Clyde W. "COVID-19 and African Americans." Jama (2020). [R]
[4] Ebadi, Maryam, and Aldo J Montano-Loza. “Perspective: improving vitamin D status in the management of COVID-19.” European journal of clinical nutrition vol. 74,6 (2020): 856-859. [R]
[5] Kakodkar, Pramath et al. “A Comprehensive Literature Review on the Clinical Presentation, and Management of the Pandemic Coronavirus Disease 2019 (COVID-19).” Cureus vol. 12,4 e7560. 6 Apr. 2020, [R]
[6] Martineau, Adrian R et al. “Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data.” BMJ (Clinical research ed.) vol. 356 i6583. 15 Feb. 2017, [R]
[7] Martineau, Adrian R et al. “Vitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis.” Health technology assessment (Winchester, England) vol. 23,2 (2019): 1-44. [R]
[8] Bikle, Daniel. “Vitamin D: Production, Metabolism, and Mechanisms of Action.” Endotext, edited by Kenneth R Feingold et. al., MDText.com, Inc., 2000. [R]
[9] Bäcker, Alex, Why COVID-19 May Be Disproportionately Killing African Americans: Black Overrepresentation among COVID-19 Mortality Increases with Lower Irradiance, Where Ethnicity Is More Predictive of COVID-19 Infection and Mortality Than Median Income (April 8, 2020). [R] [R]
[10] Lau, Frank H., et al. "Vitamin D insufficiency is prevalent in severe COVID-19." [R]
[11] Hastie, Claire E et al. “Vitamin D concentrations and COVID-19 infection in UK Biobank.” Diabetes & metabolic syndrome, vol. 14,4 561-565. 7 May. 2020, [R]
[12] Ebadi, Maryam, and Aldo J Montano-Loza. “Perspective: improving vitamin D status in the management of COVID-19.” European journal of clinical nutrition vol. 74,6 (2020): 856-859. [R]
[13] Grant, William B et al. “Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths.” Nutrients vol. 12,4 988. 2 Apr. 2020, [R]
