Definition: Diabetes mellitus is a syndrome in which the body cannot metabolize glucose (sugar) appropriately. The subsequent sustained elevated levels cause significant damage to the eyes, heart, kidneys, and other organs. Diabetes is a significant and growing public health problem; in 2014 the US Centers for Disease Control and Prevention (CDC) reported that an estimated 29 million persons in the United States were affected in 2012, up from 26 million in 2010. Of those with diabetes, 25 percent are not aware that they have the disease. An additional 86 million adults age twenty or older have prediabetes. Of these, the CDC reports that 15 to 30 percent will go on to have in type 2 diabetes if they do not reduce their weight and are not moderately physically active. Diabetes is a disease related to both genetics and environmental or lifestyle factors.
Diabetes mellitus comprises a number of different diseases, primarily type 1 and type 2 diabetes. Genetics plays a role in both types of diabetes, although both are thought to result from the interaction between genetics and the environment. In both, the body’s ability to process sugars is impaired, with consequences that can lead to death if untreated. Glucose is a simple sugar required by all cells for normal functioning. Most of the body’s glucose initially comes from carbohydrates broken down during digestion. Normally, blood glucose rises when carbohydrates are ingested. At a certain level, the blood glucose triggers the pancreas to release insulin, causing the blood glucose level to drop by increasing the uptake in muscle, fat, the liver, and the gut.
Patients with either type of diabetes have difficulty metabolizing glucose, with a subsequent rise in fasting and postprandial (after meals) blood sugar levels. In type 1 diabetes, also called juvenile-onset or insulin-dependent diabetes, this is caused by destruction of the insulin-secreting cells in the pancreas. In type 2 (adult-onset, maturity-onset, or non-insulin-dependent diabetes), cells become resistant to the effects of insulin even though the pancreas is still producing some insulin.
Homeostasis and diabetes are related because of the system of homeostatic checks and balances that allows for the proper rise and fall of glucose levels in the blood stream and within bodily tissues. The malfunction of homeostasis, leading to diabetes disease as a consequence is classified as an endocrine system disorder because diabetes can be the result of three main hormonal inconsistencies. The first two homeostatic imbalances that can lead to diabetes are when the body does not produce enough or overproduces the hormone insulin and sometimes glucagon. The third inconsistency is when a person’s body possesses nonfunctional receptor sites within target cells that cause the body to become insensitive to these same chemicals. Research shows that in many cases of diagnosed imbalanced homeostasis and diabetes disease, a combination of these disease mechanisms is present.
The pancreas, a major endocrine organ, contains special cell types, called endocrine cells, which cluster together in the islets of Langerhans and secrete insulin and glucagon, the first step in blood glucose regulation. After a meal, if the endocrine system is working in homeostatic balance, blood sugars rise and insulin prompts the cells to take up the glucose. At this point, blood sugars can be used by many body parts, like the liver and skeletal muscles, for example, as an energy-giving carbohydrate. As the majority of the glucose is used and stored by the body, insulin production is inhibited. After this inhibition, a healthy person’s homeostatic mechanism causes the glucagon levels to rise, which causes stored glycogen to