Diabetes

Seventy out of every 1,000 Americans reading this article have a disease that will, on average, shorten their lives by about 20 years. More than 20 of these 70 people are not even aware they are ill. The disease in question is diabetes, and it consumes one out of every ten health care dollars spent in the U.S. However, with proper treatment and lifestyle changes, many of its devastating complications can be prevented or delayed.

Diabetes is a chronic disease that impairs the body’s ability to use food properly. As food is digested, its components are converted into the simple sugar glucose, which is absorbed into the blood through the small intestine. The body relies on glucose as its basic fuel, but it first needs to move the glucose from the bloodstream into the muscles and organs where it’s needed. This transfer requires a hormone called insulin, produced by the pancreas. The body continually monitors blood sugar levels; in healthy people, it corrects with more insulin if the blood sugar gets too high, with less if it gets too low.

When people have diabetes, either their pancreatic cells don’t produce enough insulin or their bodies are not able to efficiently use the insulin that is made. Glucose gets trapped in the bloodstream and spills into the urine. At the same time the muscles and organs are starved for energy, the blood’s high sugar content damages the cells of many organs it flows through. If the levels are very high, they can cause coma or death.

Over time, diabetes causes destruction throughout the body. It affects the blood vessels and the heart, increasing the risk of heart disease or stroke by up to four times; two-thirds of people who have diabetes die from these complications. Many people have already damaged the blood vessels in their eyes by the time they are diagnosed, and 90 percent of them have damage after 15 years with the illness; these changes cause almost 40,000 cases of blindness each year, making diabetes the leading cause of adult-onset blindness in North America. Kidney disease is also a major complication; about 30 percent of new dialysis patients have diabetes-induced kidney failure. About 60 to 70 percent of people with diabetes have nervous system damage, causing problems like numbness or pain in the hands and feet or slowed digestion of food in the stomach. Amputations occur 10 times more frequently in people with diabetes than in people without diabetes, and the illness also impairs the immune system, making people more susceptible to serious infection.

While there is not yet a cure for diabetes, it can be controlled. The main goal of all treatment is to control blood sugar levels, but the method varies depending on the type of diabetes a person has.

Type 1 Diabetes

The most severe form of diabetes is type 1, previously known as juvenile diabetes because it is usually develops during childhood or young adulthood. Type 1 accounts for 5 to 10 percent of all diagnosed cases of diabetes and affects about one in every 400 to 600 children and adolescents. In this form of the illness, the pancreas produces little or no insulin. Although the causes are not entirely known, scientists believe the body’s immune system mistakenly attacks and destroys the insulin-producing cells in the pancreas.

Viruses may trigger the onset of type 1 diabetes because they contain proteins that look very similar to proteins found in the pancreas’ insulin-producing beta cells. Studies have also linked type 1 diabetes to the rat poison pyriminil as well as the prescription drugs pentamidine, used to treat a severe form of pneumonia, and L-asparaginase, a cancer treatment. Genetic factors are probably involved in making some people more susceptible, as type 1 diabetes tends to run in families.

The early symptoms of type 1 diabetes are frequent urination in large quantities, excessive thirst, extreme hunger all the time, sudden weight loss for no apparent reason, weakness, drowsiness, sudden vision changes, nausea and vomiting. Before the discovery of insulin in 1921, these symptoms often led to coma and death within a few weeks.

People with type 1 diabetes must check their blood sugar and take injections of insulin several times every day to prevent life-threatening consequences from blood sugar that is too high or too low. Additionally, lifestyle factors such as diet and fitness are important for maintaining health after diagnosis.

Type 2 Diabetes

More than 90 percent of people with diabetes have type 2, in which the pancreas still produces insulin but the cells of the body are not able to use it properly (a condition called insulin resistance). As the body’s need for insulin rises, gradually the overtaxed pancreas loses the ability to produce it. Type 2 was previously called adult-onset diabetes because it occurs more frequently in later life, although as childhood obesity increases it is beginning to appear in some children and adolescents.

Several risk factors increase the chance that a person will develop type 2 diabetes. Lifestyle factors such as physical inactivity and obesity increase the risk for type 2 diabetes by more than tenfold. Being heavy around the belly (apple-shaped) appears to be worse than being heavy in the thighs (pear-shaped). Type 2 disease also runs in families, suggesting a strong genetic component. Certain racial and ethnic groups are affected more frequently; in the U.S., African-Americans, Latinos, American Indians, Alaskan Natives, Asian Americans and Pacific Islanders are around twice as likely as Caucasians to develop the illness. Additionally, age plays a role. More than 20 percent of Americans over age 60 have type 2 diabetes, and half of all new diagnoses occur in this age group. Finally, people who have high blood pressure or high cholesterol may be at higher risk for developing type 2 diabetes, particularly if they are overweight and sedentary, as these problems occur together in a condition called the metabolic syndrome.

While the symptoms of type 2 diabetes can be similar to those of type 1, they appear far more gradually; on average, people have type 2 diabetes for seven years before it is recognized. Often they are diagnosed when they seek evaluation for fatigue, blurry vision, recurrent or hard-to-heal infections, or tingling and numbness in hands or feet, or when they develop diabetes-related health conditions such as heart disease.

For reasons that remain unclear, carrying excess body fat causes insulin resistance. Consequently, the most important components of type 2 diabetes management are diet and exercise. Dropping weight and gaining muscle help the body use insulin more efficiently, and some people can manage their diabetes with these measures alone. If the pancreas still produces a fair amount of insulin, oral medications can boost the production to overcome insulin resistance; after many insulin-producing cells have burned out, oral medications are no longer enough and supplemental insulin must be given by injection. Many people with diabetes must also take medication to control their blood pressure and cholesterol and protect their kidneys.

Before people develop type 2 diabetes they almost always have a period of pre-diabetes, where their blood sugar levels are slightly higher than normal, particularly after consuming meals. This condition used to be called latent diabetes or borderline diabetes, and it affects an estimated 40 percent of the adult population over age 40 in the U.S. Fortunately, studies have shown that people with pre-diabetes who lose weight and increase their physical activity can prevent or delay progression to type 2 diabetes.

Gestational Diabetes

Pregnant women who have never had high blood sugar before but develop it during pregnancy are said to have gestational diabetes. About four percent of pregnant women develop the condition, which generally appears in the later stages of pregnancy. Similar to type 2 diabetes, gestational diabetes is caused by insulin resistance.

Hormones produced by the placenta to support the baby’s growth also block the action of insulin in the mother’s body. Consequently, women’s insulin requirements may increase by threefold during pregnancy. If the pancreas cannot keep up, blood sugar levels rise for the mother and the fetus.

All pregnant women are screened for gestational diabetes in the later stages of pregnancy because untreated diabetes can create problems for both mother and baby. The high blood sugar level in fetal circulation triggers the baby’s pancreas to begin producing insulin and the baby grows too much, storing the extra sugar as fat. These babies can become so large that they damage their shoulders passing through the birth canal. As newborns they may experience breathing problems, and their overdeveloped pancreatic cells continue to produce extra insulin, causing low blood sugar after birth. They are more likely to be overweight as children and to develop type 2 diabetes as adults.

Treatment for gestational diabetes includes special meal plans, scheduled physical activity and daily blood sugar testing. Some pregnant women need injections of insulin (which is safe to use because it does not cross the placenta) to keep their blood sugar within the normal range.

Gestational diabetes usually resolves after pregnancy, but a small number of women remain with type 2 diabetes after the birth, and all women with gestational diabetes face increased risk for diabetes down the road. Sixty-five percent develop gestational diabetes again in subsequent pregnancies, and 30 to 40 percent develop type 2 diabetes within a decade.

Diagnosis of Diabetes

The preferred test for diagnosing diabetes is the fasting plasma glucose (FPG) test, a blood test done in the morning after an overnight fast. Normal levels are 99 mg/dL and below. Levels between 100 and 125 indicate pre-diabetes, and levels above 125—if confirmed with a repeat test on another day—mean a diagnosis of diabetes.

The oral glucose tolerance test (OGTT) is more sensitive than the FPG test for picking up pre-diabetes, but it is less convenient to administer. Blood glucose is measured after an overnight fast, as with the FPG test, and then the patient is given a glucose mixture to drink. Blood glucose levels are measured again two hours later; levels of 139 or below are in the normal range, levels between 139 and 199 show pre-diabetes, and levels of 200 and above indicate diabetes.

A blood glucose test drawn at random during the day can be used to test for diabetes, although this method is less reliable. A level of 200 mg/dL or greater can indicate diabetes if it is accompanied by symptoms such as excessive urination, persistent thirst or unexplained weight loss. The result should be confirmed on another day with an FPG test.

All people aged 45 or over should get an FPG test to screen for diabetes, especially if they are overweight. People under age 45 should consider getting tested if they are overweight and have one or more factors increasing their risk for diabetes, such as family history, a high-risk ethnic group, high blood pressure or high cholesterol, etc. If pre-diabetes develops, testing should be repeated every one to two years to watch for any progression to diabetes. If possible symptoms of diabetes develop at any age, testing should be done as soon as possible.

Diabetic Emergencies

One of the most important advances in diabetes treatment and control has been the ability to measure and monitor blood sugar levels at home. People with all types of diabetes must understand how the disease works and learn how to test and manage their blood sugar levels.

The three critical elements for controlling diabetes are food, exercise and insulin. The rule of thumb is that food makes the glucose level rise and exercise and insulin make the glucose level fall. Diabetes control is a constant balancing act involving these three factors, especially for people with type 1 diabetes. Other factors that can affect the balance include infection, fatigue, excitement, anxiety, hormonal changes and periods of growth. If the balance is lost, one of two diabetic emergencies can emerge: hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar).

Hypoglycemia, sometimes called insulin shock, can occur if a person using insulin eats too little food, doesn’t eat soon enough, takes too much insulin or exercises too much. Common symptoms include sudden hunger, crankiness, inappropriate responses, confusion, headache, dizziness, inattention, lack of coordination, drowsiness, perspiration, pale complexion and trembling; people have their own characteristic combinations of these symptoms, and it’s important for them to identify their typical responses because the condition can lead to unconsciousness if not corrected quickly by eating sugary foods. Some people show no preliminary symptoms and therefore need to monitor their blood sugar levels more frequently. If someone experiencing hypoglycemia becomes unconscious, honey or syrup should be rubbed inside the person’s cheek where it can be absorbed without posing a risk of choking.

Hyperglycemia can be equally dangerous if it is severe and untreated. A condition called diabetic ketoacidosis (DKA) can develop, usually seen in people with type 1 diabetes. Since the body can’t use any glucose to supply its energy needs, it instead burns fats, forming by-product acids called ketones that poison the system. Symptoms develop over hours to days and include extreme thirst; dry, hot skin; loss of appetite; drowsiness and lethargy; heavy or labored breathing; and a sweet, fruity or wine-like odor on the breath. Ketones and glucose can be detected in the urine as well as the blood. Eventually the condition progresses to stupor and coma, presenting a life-threatening emergency that requires hospitalization.

Diet and Exercise

Eating well-balanced meals in the correct amounts helps keep blood glucose level as close to normal as possible. Consultation from a dietician is helpful for developing a personal meal plan outlining the types and quantities of food that can be chosen for meals and snacks. The plan should aim for a fixed number of calories each day and should be low in fat. Concentrated sugars should be avoided because the body cannot mobilize insulin fast enough to counter their rapid effect on blood sugar levels. Many systems are available to help people follow their diabetes meal plans: the Food Guide Pyramid, Rate Your Plate, the Diabetic Exchange Lists, and carbohydrate counting.

Exercise is also important, particularly for people with type 2 diabetes, because it helps control weight and reduces demand on the pancreas to produce insulin. It is important to maintain a regular pattern of eating, exercising, and resting. Changes of schedule require adapting the diet or insulin dosages appropriately. For instance, if dinner will be very late, a light snack will be needed at the normal dinner hour; similarly, a snack may be necessary before or after strenuous activities.

Looking into the future, there is increasing hope that diabetes and its related problems may someday be cured. Researchers are beginning to understand the autoimmune process that destroys insulin-producing cells, identifying many of the genes that place people at risk for diabetes, and refining new treatments such as pancreas transplants. Gene therapy has been used successfully to cure diabetes in mice by converting some liver cells into insulin-producing pancreatic cells, and stem cell research may present similar opportunities, changing the face of diabetes treatment.

by Gillian Friedman, MD

Juvenile Diabetes Research Foundation
www.jdrf.org
800.JDF.CURE (800.533.2873)

American Diabetes Association
www.diabetes.org
800.DIABETES (800.342.2383)

National Diabetes Education Program
www.ndep.nih.gov
800.438.5383

ABILITY Magazine
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