By the time of recruitment (that is, ≥5 years from diagnosis), the difference in BMI between those with type 1 and type 2 diabetes was smaller (26.5 kg/m2 [23.1–29.3 kg/m2] versus 29.7 kg/m2 [26.6–34.5 kg/m2]) although still significant (P <0.001), and the ROC AUC was low, highlighting the reduced discriminative ability of this as a clinical marker to differentiate between type 1 and 2 diabetes once the patient was receiving insulin. This evidence concerns the gene INS and type 2 diabetes mellitus.