Contributor: Gordon K. Klintworth
Diabetes mellitus type II (non-insulin dependent diabetes, maturity-onset diabetes mellitus) is one of the major forms of diabetes mellitus. It is an extremely common heterogenous disorder and affects 5% of adult Americans. In contract to diabetes mellitus type I the blood insulin level is normal or higher than normal in diabetes mellitus type II and the disease is not due to a destruction of beta cells in the islets of Langerhans in the pancreas, but the result of an inability to meet an increased need for insulin. Most cases of  diabetes mellitus type II become manifest with a gradual and often subtle onset in overweight persons 30-40 years old. Risk factors for diabetes mellitus type II include obesity and a strong genetic predisposition. Environmental factors also play a role.There is no association with the MHC. Affected persons lack antibodies to the cells of the pancreatic islets. Late lesions in the pancreas include fibrosis and amyloid deposits in the pancreatic islet cells. Diabetes mellitus type II can be controlled on a diet, but sometimes insulin or drugs are needed to manage the disease. Diabetes mellitus type II is a complex disorder with an impaired function of the beta islet cells in the pancreatic. There is also an insulin resistance by peripheral tissues that require insulin. In contrast to diabetes type I diabetes mellitus type II is not an autoimmune disease. Some beta cells are present in the pancreas, but there are many fewer than normal. Late pancreatic lesions include fibrosis and deposits of amyloid [amyloidosis] in regions of islet cells. The major constituent of the amyloid is amylin or islet amyloid polypeptide. Several subgroups of  diabetes mellitus type II  are recognized. They include the the various types of maturity-onset diabetes of the young. Complications of diabetes mellitus result largely from the severity of the disease and the chronicity of the hyperglycemia. They include coma, diabetic retinopathy, cataracts [cataract], atherosclerosis (coronary artery atherosclerosis [atherosclerosis - coronary artery], peripheral occlusovascular disease [occlusovascular disease - peripheral]), diabetic neuropathy, renal disease (glomerulosclerosis [glomerulosclerosis - diabetic], necrotizing papillitis, pyelonephritis), bacterial infections, and fungal infections (including zygomycosis).