Definition, epidemiology, diagnosis and classification

Type 2 diabetes

• Previously known as non-insulin-dependent diabetes (NIDDM)
• In adults it is common and is the predominant form of diabetes
• In children it is uncommon but is being reported more frequently in many countries in association with rising rates of obesity
• Occurs more commonly than type 1 diabetes in Japanese children, and certain ethnic groups are at high risk, e.g. Native Americans and Canadians, Mexican/Hispanic Americans, African-Americans, South Asian Indians in India and Europe, Pacific Islanders, Australian Aborigines

Onset

• 80–90% are obese at the time of diagnosis (in the absence of obesity, consider genetic defects of beta-cell function)
• Most children and adolescents are asymptomatic or have minimal symptoms at diagnosis
• Occasionally ketoacidosis may develop in association with infections or other major stress

Etiology

• Unknown
• Genetic (polygenic) factors are important
  [Identical twins have 100% concordance for type 2 diabetes
  Positive family history is likely especially when parents tested with OGTT]
• Lifestyle factors such as overeating and little exercise may have an important influence
• The sequence of intrauterine growth retardation (thrifty phenotype or genotypic variation) excess postnatal nutrition obesity hyperinsulinemia and insulin resistance diabetes, hypertension, cardiovascular disease (metabolic syndrome) has major worldwide implications

Principles of management

• Reduction in energy intake to recommended values in order to control weight gain or reduce obesity
• Exercise and healthy lifestyle
• Oral hypoglycemic agents, e.g. sulfonylureas and metformin (also consider thiazolidinediones and possibly alpha-glucosidase inhibitors)
• Insulin treatment should not be delayed if good glycemic control is not achieved by the above measures, particularly in the adolescent who is still growing

Screening

• Routine screening for glycosuria in most populations is not cost-effective

• Selective screening or monitoring of urine or BG in populations or individuals at high risk may be advisable

• All Japanese children have regular school urine screening partly because of the higher incidence of type 2 diabetes
• Differentiation between non-obese type 2 and type 1 diabetes may be helped by measuring islet cell autoantibodies

Community implications and prevention

• Research is needed to understand the biology of this phenomenon
• Programs to prevent obesity are urgently needed