Diabetes and Glucose Biosensors

A lecture by Dr. Hiroko Karan, Dean of the School for Science, Health and Technology, 

Medgar Evers College, CUNY.

[Photo by Antony Wong]  Dean Karan listened intently to questions posed by the audience pertaining to the differences between Type I and Type II diabetes.

Updated September 15, 1998
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· Diabetes mellitus is a disease caused by a deficiency of insulin, which is a hormone secreted by the pancreas.

· About 16 million Americans have diabetes, but only about 10 million have been diagnosed. Approximately 798,000 new cases of diabetes are diagnosed annually in the United States.

· The number of persons diagnosed with diabetes has increased sixfold, from 1.6 million in 1958 to 10 million in 1997. Diabetes is the nation's seventh leading killer and contributed to about 187,800 deaths in 1995.

· Diabetes is classified into two main types: type 1 and type 2 . Type 1 diabetes (insulin-dependent), affects 5%-10% of those with diabetes and most often occurs during childhood or adolescence. Type 2 diabetes (non-insulin- dependent) is the more common type, affecting 90%-95% of those with diabetes. Type 2 diabetes usually occurs after age 40.

· Diabetes and its complications occur among Americans of all ages and racial/ethnic groups, but the elderly and certain racial/ethnic groups are more commonly affected by the disease. About 18% of Americans 65 years of age and older have diabetes.

· Diabetes patients risk debilitating complications such as blindness, kidney disease, and lower-extremity amputations.

· Cardiovascular disease is 2-4 times more common among persons with diabetes; the risk of stroke is 2-4 times higher; 60%-65% have high blood pressure; and 60%-70% have mild to severe diabetic nerve damage.

http://www.cdc.gov/od/oc/media/fact/diabetes.htm

[Photo by Antony Wong]  The audience asked if diabetes developed after forty years of age could be transmitted to their offspring.  Dean Karan answered by stating that it wouldn’t be considered hereditary if it weren’t genetically transmitted.

Diabetes mellitus is a group of diseases characterized by high levels of blood glucose resulting from defects in insulin production, insulin action, or both. Diabetes can be associated with serious complications and premature death, but people with diabetes can take steps to control the disease and lower the risk of complications.

Type 1 diabetes was previously called insulin-dependent diabetes mellitus (IDDM) or juvenile-onset diabetes. Type 1 diabetes develops when the body's immune system destroys pancreatic beta cells, the only cells in the body that make the hormone insulin that regulates blood glucose. This form of diabetes usually strikes children and young adults, who need several insulin injections a day or an insulin pump to survive. Type 1 diabetes may account for 5% to 10% of all diagnosed cases of diabetes. Risk factors for type 1 diabetes include autoimmune, genetic, and environmental factors.

Type 2 diabetes was previously called non-insulin-dependent diabetes mellitus (NIDDM) or adult-onset diabetes. Type 2 diabetes may account for about 90% to 95% of all diagnosed cases of diabetes. It usually begins as insulin resistance, a disorder in which the cells do not use insulin properly. As the need for insulin rises, the pancreas gradually loses its ability to produce insulin. Type 2 diabetes is associated with older age, obesity, family history of diabetes, prior history of gestational diabetes, impaired glucose tolerance, physical inactivity, and race/ethnicity. African Americans, Hispanic/Latino Americans, American Indians, and some Asian Americans and Pacific Islanders are at particularly high risk for type 2 diabetes. Type 2 diabetes is increasingly being diagnosed in children and adolescents.

Gestational diabetes is a form of glucose intolerance that is diagnosed in some women during pregnancy. Gestational diabetes occurs more frequently among African Americans, Hispanic/Latino Americans, and American Indians. It is also more common among obese women and women with a family history of diabetes. During pregnancy, gestational diabetes requires treatment to normalize maternal blood glucose levels to avoid complications in the infant. After pregnancy, 5% to 10% of women with gestational diabetes are found to have type 2 diabetes. Women who have had gestational diabetes have a 20% to 50% chance of developing diabetes in the next 5-10 years.

Other specific types of diabetes result from specific genetic conditions (such as maturity-onset diabetes of youth), surgery, drugs, malnutrition, infections, and other illnesses. Such types of diabetes may account for 1% to 5% of all diagnosed cases of diabetes.

· In order to survive, people with type 1 diabetes must have insulin delivered by injections or a pump.

· Many people with type 2 diabetes can control their blood glucose by following a careful diet and exercise program, losing excess weight, and taking oral medication.

· Many people with diabetes also need to take medications to control their cholesterol and blood pressure.

· Among adults with diagnosed diabetes, about 11% take both insulin and oral medications, 22% take insulin only, 49% take oral medications only, and 17% do not take either insulin or oral medications.

· Impaired glucose tolerance (IGT) and impaired fasting glucose (IFG) are considered to be prediabetic conditions, and studies suggest that they may be reversible.

· IGT is a condition in which the blood sugar level is elevated (between 140 and 199 milligrams per deciliter or mg/dL after a 2-hour oral glucose tolerance test), but is not high enough to be classified as diabetes.

· IFG is a condition in which the fasting blood sugar level is elevated (between 110 and 125 mg/dL after an overnight fast) but is not high enough to be classified as diabetes.

· Among U.S. adults 40-74 years of age, 16.0 million (15.6%) have IGT and 10.0 million (9.7%) have IFG.

 

Research studies in the United States and abroad have found that lifestyle changes can prevent or delay the onset of type 2 diabetes among high-risk adults. These studies included people with IGT and other high-risk characteristics for developing diabetes. Lifestyle interventions included diet and moderate-intensity physical activity (such as walking for 2 1/2 hours each week). For both sexes and all age and racial and ethnic groups, the development of diabetes was reduced 40% to 60% during these studies that lasted 3 to 6 years.

Studies have also shown that medications have been successful in preventing diabetes in some population groups. In the Diabetes Prevention Program, a large prevention study of people at high risk for diabetes, people treated with the drug metformin reduced their risk of developing diabetes by 31%. Treatment with metformin was most effective among younger, heavier people (those 25-40 years of age who were 50 to 80 pounds overweight) and less effective among older people and people who were not as overweight.

There are no known methods to prevent type 1 diabetes. Several clinical trials are currently in progress.

· Research studies in the United States and abroad have found that improved glycemic control benefits people with either type 1 or type 2 diabetes. In general, for every 1% reduction in results of A1C blood tests, the risk of developing microvascular diabetic complications (eye, kidney, and nerve disease) is reduced by 40%.

· Blood pressure control can reduce cardiovascular disease (heart disease and stroke) by approximately 33% to 50% and can reduce microvascular disease (eye, kidney, and nerve disease) by approximately 33%.

· In general, for every 10 millimeters of mercury (mm Hg) reduction in systolic blood pressure, the risk for any complication related to diabetes is reduced by 12%.

· Improved control of cholesterol and lipids (for example, HDL, LDL, and triglycerides) can reduce cardiovascular complications by 20% to 50%.

· Detecting and treating diabetic eye disease with laser therapy can reduce the development of severe vision loss by an estimated 50% to 60%.

· Comprehensive foot care programs can reduce amputation rates by 45% to 85%.

· Detecting and treating early diabetic kidney disease can reduce the development of kidney failure by 30% to 70%.

http://www.cdc.gov/diabetes/pubs/general.htm

[Photo by Antony Wong]  Dean Karan demonstrated the new glucose biosensors used in the measurement of blood sugar levels in diabetics.  Even though it is a vast improvement over the older method of drawing blood from the vein, it still requires frequent pricking of the fingers.

Coordinator: Thomas Tam