HMOX1 and diabetes mellitus: Given the associations between the genetic variants and the risk of cardiovascular and kidney disease, the inverse relationship between HO-1 expression and diabetes, and the association between plasma HO-1 concentrations and risk of T2D, the question arises, what is the role of the genetic variants and the HO-1 serum concentrations for the risk of cardiovascular and kidney disease in individuals with T1D.