ACE and angioedema: Given the low incidence of angioedema associated with ACEi, it is thought that individuals are only affected if they have an additional risk factor, such as smoking (due to reduced NEP and dipeptidyl peptidase IV activity in smokers), black race (due to ACE gene polymorphisms) or hereditary angioedema (for example due to C1 inhibitor deficiency) [29, 30].