Type 2 diabetes is estimated to represent 90% of all cases of diabetes. It’s a metabolic disease that develops due to a deteriorated function of the beta cells, in combination with a substantial insulin resistance in the body. Insulin resistance is a condition in which normal amounts of insulin are inadequate to produce an appropriate glucose metabolizing response in fat, muscle and liver cells. Insulin resistance is one of the fundamental defects in type 2 diabetes and may appear many years prior to the onset of clinical disease.
It has previously been considered as an adult-onset form of diabetes. However this is not always the case today since young individuals have been diagnosed with type 2 diabetes. Many type 2 diabetic patients are also obese, thereby linking these two metabolic disorders since obesity is closely associated with insulin resistance. Insulin resistance is also found with a cluster of other risk factors including stroke, nonalcoholic fatty liver disease, polycystic ovary syndrome, lipodystrophies, asthma, some cancers and Alzheimer´s disease.
Clearly, genetic factors play a role in the manifestation of type 2 diabetes; however, diabetes-related polymorphisms may only explain a fraction of the variance in quantitative glycaemic traits. Therefore environmental factors, such as diet and exercise, can have a profound impact on metabolic pathways controlling glucose and lipid metabolism.