• epidemiology
• pathology
• type 2 diabetes
• adolescence

The definition of diabetes mellitus (DM) was recently changed by the American Diabetes Association to a fasting plasma glucose value of at least 126 mg/dl (6.9 mmol/l), on the basis of increased risk of the complication of retinopathy.¹ It has been estimated that worldwide approximately 154 million people have diabetes,² with up to one third of the cases remaining undiagnosed in developed countries such as the USA.³ Its human cost is considerable with morbidity from retinopathy, neuropathy, renal failure, and vascular disease, in addition to the socioeconomic burden. Additional lifetime health costs attributable to DM have been estimated at £19 649 per affected individual in the UK.⁴

Since the introduction of insulin therapy, a clear distinction has been established between the form of DM where insulin is immediately needed (type 1 or insulin dependent DM), and that where there is a danger of hypoglycaemia, where insulin therapy represents a “luxury” (type 2 diabetes (T2D) or non-insulin dependent DM). The latter is far more frequently associated with obesity and a “gluttonous appetite”.⁵ Age is a distinguishing feature: an age ⩾40 years predicts T2D with a sensitivity of 97% and a specificity of 100%.⁶

However, nearly 25 years ago, North American authors first drew attention to the occurrence of T2D in young Pima Indians.⁷ Pinhas-Hamiel from Cincinnati highlighted the incidence of this condition in black adolescents;⁸ subsequently Hispano-American adolescents have been found to be affected. This concerned US health authorities sufficiently for the Centers for Disease Control and Prevention to order a specific committee to investigate.¹⁰