Vitamin D and COVID-19: Role of ACE2, age, gender, and ethnicity.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, disproportionally targets older people, particularly men, ethnic minorities, and individuals with underlying diseases such as compromised immune system, cardiovascular disease, and diabetes. The discrepancy in COVID-19 incidence and severity is multifaceted and likely involves biological, social, as well as nutritional status. Vitamin D deficiency, notably common in Black and Brown people and elderly, is associated with an increased susceptibility to many of the diseases comorbid with COVID-19. Vitamin D deficiency can cause over-activation of the pulmonary renin-angiotensin system (RAS) leading to the respiratory syndrome. RAS is regulated in part at least by angiotensin-converting enzyme 2 (ACE2), which also acts as a primary receptor for SARS-CoV-2 entry into the cells. Hence, vitamin D deficiency can exacerbate COVID-19, via its effects on ACE2. In this review we focus on influence of age, gender, and ethnicity on vitamin D-ACE2 interaction and susceptibility to COVID-19.