Non-insulin dependent diabetes mellitus (NIDDM) in minority youth: research priorities and needs

The prevalence of non-insulin dependent diabetes mellitus (NIDDM) is increasing in Native American and African-American youth, with females more frequently affected than males. This increase is related to increasing rates of obesity and to the greater demand for insulin at adolescence. This review examines the epidemiologic data about NIDDM in minority youth and addresses questions about the type of diabetes minority youth have, the relative contributions of environment and genetics to their diabetes, and whether prevention or control is possible. The heterogeneity of NIDDM in the minority youth population includes: typical NIDDM; atypical diabetes mellitus (ADM), which has been described in a substantial number of African-American youngsters; and a small proportion with a range of defects in the pathway of insulin action. Clinical and experimental evidence that insulin resistance or insulin deficiency is the primary defect in NIDDM are reviewed, as is evidence that fetal undernutrition may be a contributing factor. The numerous reports of linkages, associations, and mutations or polymorphisms in candidate genes account for a very small proportion of non-type 1 diabetes. Environmental and genetic contributors to obesity are also important. Research issues relating to the questions discussed include the need for data comparing various populations and assessing risk factors associated with the epidemic of NIDDM and obesity, costs to the health system and attendant personal and societal costs, clarification of the types of NIDDM in minority populations that will permit appropriate therapy and counseling, and extensive studies of environmental and genetic factors. Genetic studies include a genome wide search and continued analysis for candidate genes for both NIDDM and obesity. Environmental factors for study include the role of fetal and perinatal nutrition and drug exposure. Finally, collaborative multicenter studies are needed of prevention or control of obesity and NIDDM.