Epidemiología, genética y mecanismos patogénicos de la diabetes mellitus

The effect that the microvascular and macrovascular complications of diabetes mellitus have on morbidity, mortality and quality of life has led to the disorder becoming one of today's most important public health problems. Changes in lifestyle, resulting in a predominantly sedentary population with a high calorie intake, has influenced both the incidence and prevalence of diabetes mellitus, irrespective of geographical location. It has been estimated that, over the next two decades, the prevalence of diabetes mellitus in developed countries could increase from 6-10% to 20% in many regions. These projections refer specifically to type-2 diabetes mellitus, which constitutes 90% of all known cases of diabetes. The pathogenetic mechanisms underlying type-2 diabetes mellitus principally involve pancreatic beta cell dysfunction and a state of insulin resistance. Reductions in the action of insulin in peripheral tissues and the liver result in a compensatory state of hyperinsulinemia during early disease stages. However, with time, the pancreatic reserve continues to decrease. The outcome is chronic hyperglycemia which, combined with the accumulation of free fatty acids, produces a 'toxic' environment for beta cells. At the same time, central obesity, with fat deposition in adipocytes and the secretion of adipocytokines, increases insulin resistance further, ultimately leading to beta cell failure.