[Epidemiology and classification for diabetes mellitus].

Diabetes is a chronic metabolic disorder cause by an absolute or relative insulin deficit. Diabetes is characterized by the presence of hyperglycemia and by metabolic alterations regarding all the immediate principle nutrients: carbohydrates, lipids and proteins. Diabetes causes high morbidity and mortality derived by chronic micro-vascular complications such as retinopathy, nephropathy, or neuropathy and macro-vascular complications such as ischemic cardiac problems, cerebral vascular accidents, peripheral vascular disorders. The layman's belief that diabetes occurred only due to hereditary factors has been changing as numerous studies have shown that diabetes deals with a group of heterogenous disorders which develop as a combination of hereditary and environmental factors.