Because patients with diabetes, particularly the elderly with type 2 diabetes (T2DM), are at a higher risk of severe disease or death due to SARS-CoV-2 infection than age-matched individuals without diabetes, it is of interest to recall that a consistent body of evidence has linked magnesium deficiency to alterations of insulin sensitivity, including metabolic syndrome and T2DM [39]. This evidence concerns the gene INS and diabetes mellitus.