Diabetes mellitus is a disease of glucose metabolism that is defined by blood glucose levels. There are three types of diabetes: insulin dependent diabetes mellitus, IDDM (type I), non-insulin dependent diabetes mellitus, NIDDM (type II), and gestational diabetes (onset occurs in women during pregnancy).

In IDDM, the pancreas does not make enough insulin. Insulin is a hormone that signals fat, muscle, and liver cells (target cells) to take glucose from the blood plasma into the interior on the cells to be used for cellular respiration. Individuals with IDDM must take insulin to manage their blood glucose levels. Studies with twins have shown that concordance for IDDM (the occurrence of IDDM in both individuals) is minimal, therefore the inheritance factor for IDDM is suspected to be minimal. Researchers believe that both environmental factors and viral antigens are mostly responsible for IDDM.

NIDDM is associated with obesity and...