INS and type 2 diabetes mellitus: Even in the studies (cited above) in which insulin-treated patients with type 2 diabetes are compared with other, non-insulin-treated, persons with type 2 diabetes, those receiving insulin can differ in many ways from their controls: they are usually older, with a more severe form of diabetes, a higher burden of diabetic complications and comorbidities, and a poorer glycemic control—all factors which may explain, at least in part, observed differences in the incidence of cancer.