Early-onset insulin-resistant diabetes in obese Caucasians has features of typical type 2 diabetes, but 3 decades earlier.

Obesity has dramatically increased in Irish adolescents and young adults and is related to changes in physical activity and diet (1,2). Severe obesity is associated with a much earlier presentation of type 2 diabetes (3—6), as noted in Irish Caucasian patients (7). Most studies of early-onset type 2 diabetes have been in minority populations with higher risk of type 2 diabetes than Caucasians (4—6). The potential for diabetes complications in these young individuals has immediate implications for diagnosis and treatment and longer-term implications for public health. We measured insulin resistance, insulin secretion, and a range of cardiovascular risk markers in an obese group of young Irish subjects with type 2 diabetes and compared them with a matched group of obese nondiabetic subjects and a representative group of older subjects with type 2 diabetes. All of the subjects were from the same clinic, and all were matched for obesity and duration of diabetes. Eleven subjects with early-onset (age 40 years) type 2 diabetes were recruited, as well as 13 nondiabetic control subjects who were age and obesity matched to the young type 2 diabetic group. The protocol had ethical approval, and written informed consent was obtained. An oral glucose tolerance test was used to confirm glucose tolerance. ### Intravenous glucose tolerance test An insulin-modified frequently sampled intravenous glucose tolerance test was performed (8,9). Oral hypoglycemic agents were withheld for 7 days before the …