Studies show that as of 2012, close to 30 million Americans have diabetes, and around 86 million adults are at risk of developing the disease (prediabetes). As of 2010, diabetes ranks as the seventh leading cause of death in the US, although research shows that it is still underreported as a cause of death.
Diabetes mellitus, or simply diabetes, is a disorder of glucose (sugar) metabolism that results in elevated blood sugar levels. The condition includes different types, which are classified according to cause.
Glucose, or sugar from food, is normally absorbed by the cells of the body and used as a source of energy. The process by which this occurs is facilitated by a hormone called insulin, which is produced by special cells in the pancreas. After ingesting and digesting food, glucose levels in the blood increase and the pancreas is stimulated to produce insulin to initiate glucose absorption into the cells of the brain, the muscles, the heart, and other organs of the body. This is followed by a gradual decline in glucose levels in the blood, which later signals the body to ingest more food for energy. However, the normal process of glucose utilization is disrupted in people with diabetes.
The American Diabetes Association defines diabetes mellitus as "a condition characterized by hyperglycemia resulting from the body's inability to use blood glucose for energy." Hyperglycemia, or excessive glucose in the blood, can result in glucose being passed in the urine and, over a long period of time, lead to accumulation in blood vessels and other parts of the body, causing serious damage and complications. Furthermore, although blood sugar levels are high, the body is not able to use glucose as a source of energy, which leads to further complications.
There are different types of diabetes:
Type 1 diabetes. This is an autoimmune condition which occurs when the body's immune system attacks and destroys the normal insulin-producing cells of the pancreas. This results in the pancreas producing little or no insulin. To survive, a person who has this type of diabetes must receive insulin injections daily. It is usually diagnosed in children and young adults, and accounts for up to ten percent of diagnosed cases of diabetes in the US.
The symptoms of type 1 diabetes include constant hunger, increased thirst, frequent urination, weight loss, fatigue and blurring of vision. People who are not immediately diagnosed or treated can lapse into a coma (diabetic ketoacidosis) and die.
Type 2 Diabetes. This is the most common type, accounting for up to 90% of cases, and is associated with overweight or obesity, older age, physical inactivity, hereditary and genetic factors, and a history of abnormally high blood sugar levels during pregnancy (gestational diabetes). In this type of diabetes, the pancreas is able to produce enough insulin, or even higher than normal levels of it, but the body is not able to use it effectively (insulin resistance). In time, the body produces less insulin and glucose builds up, leading to a gradual onset of symptoms similar to those of type 1 diabetes. However, some people do not develop symptoms until complications develop and are not diagnosed earlier.
Gestational Diabetes. This type of diabetes develops during pregnancy. It is common among women who have a family history of diabetes. Blood sugar levels may decrease after the birth of the baby, but they have an increased risk of developing type 2 diabetes within five to ten years.
Pre-diabetes. This is a condition in which a person has higher than normal blood glucose levels, but not high enough to be diagnosed as diabetes. They are at risk of developing type 2 diabetes, as well as an increased risk of heart attack and stroke. Studies suggest, however, that increased physical activity and weight loss can prevent them from developing the disease, or delay its onset, since these interventions increase the body's sensitivity to insulin.
There are different ways to diagnose diabetes, which include a doctor's evaluation of your medical history, physical examination, and laboratory tests. Laboratory tests include:
Glycated hemoglobin test (A1C). This is a blood test that measures a patient's average blood sugar level for the past two or three months. The test does not require a patient to fast beforehand because it measures the percentage of blood sugar already attached to hemoglobin, a protein found in the red blood cells. The higher the blood sugar levels, the higher the amount of hemoglobin with sugar attached. A1C levels of 6.5% or higher indicate diabetes, while A1C levels between 5.7% and 6.4% indicate prediabetes. A level below 5.7% is normal.
Fasting blood sugar test. Also called Fasting Plasma Glucose (FPG), this blood test is performed after an overnight fast. Blood sugar levels less than 100 mg/dL (5.6 mmol/L) are considered normal, while levels of 126 mg/dL (7 mmol/L) or higher (taken twice) indicate diabetes. Levels between 100 and 125 mg/dL (5.6 to 6.9 mmol/L) are considered prediabetes.
Oral glucose tolerance test. For the OGTT, the fasting blood sugar level is first measured. Then the patient is asked to drink a sweet liquid and blood sugar levels are periodically tested over the next two hours. A normal blood sugar level is less than 140 mg/dL (7.8 mmol/L), while a test result of more than 200 mg/dL (11.1 mmol/L) after 2 hours suggests diabetes. Readings between 140 and 199 mg/dL (7.8 mmol/L and 11.0 mmol/L) are classified as prediabetes.
Many people are not aware that they are at risk of developing diabetes, or that they already have the disease. If you suspect you have diabetes, experience any of the symptoms mentioned, or are aware of any risk factors, such as family history of diabetes, obesity, and sedentary lifestyle, it is best to ask your doctor for a test as part of your yearly medical check-up. Diabetes is linked with various conditions, and there is no cure for it, but in most cases it can be controlled, and complications can be prevented.
WebMD. Diabetes – Overview.
Mayo Clinic. Diabetes.
American Diabetes Association. Diabetes Basics.