Modern concepts of diabetes and its pathogenesis

Diabetes mellitus affects a large number of individuals and represents a syndrome which is characterized by chronic hyperglycemia. Since blood glucose is controlled by a number of mechanisms, several abnormalities of different etiology and pathogenesis may cause hyperglycemia. The major types of diabetes are non-insulin dependent (Type 2) diabetes (NIDDM) and insulin- dependent (Type 1) diabetes (IDDM). NIDDM can affect as much as 3–4 percent of the population in Western Europe and North America and is probably a heterogeneous disease with multiple etiologies. Obesity is one of the suspected factors. Insulin receptor defects and mutant insulin molecules are etiological factors for only a few IDDM patients. In the majority of patients, onset starts after the age of 40, and about 60–90 percent of the patients are obese. Since most of the problems discussed in this book are less relevant to NIDDM, the modern concepts of diabetes and its pathogenesis that will be discussed in this chapter will refer to insulin-dependent (Type 1) diabetes mellitus (IDDM).