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There is an estimated 12 million Americans who have diabetes--children, adults, and pregnant women.
Diabetes can be life-threatening--but only if blood sugar (glucose) rises or falls
considerably above or below the normal range. Those who keep their blood glucose close to normal will be able to live normal lives; however, it may take some background information and some lifestyle changes.
What is Diabetes?
Background Information
Diabetes is known as "diabetes mellitus," diabetes is from the Greek for excessive urination, a symptom the ancients noticed, and mellitus, from the Latin for honey--diabetic urine is filled with sugar and is sweet..
There are three types of diabetes: type I, type II, and gestational diabetes. All of them are a little different. But everyone with diabetes has one symptom in common: Little or no ability to move sugar--or glucose--out of the bloodstream and into the cells (where it is the body's primary fuel).
Everyone has glucose in their blood. Glucose comes from food. When we eat, the digestive process breaks carbohydrates down into glucose, which is absorbed into the blood in the small intestine.
People who do not have diabetes rely on insulin, a hormone made in the pancreas, to move glucose from the blood into the body's cells. But people who have diabetes either do not produce insulin or cannot efficiently use the insulin they produce. Without insulin they cannot move glucose into the cells. Glucose accumulates in the blood, a condition called hyperglycemia ("hyper" = too much, "glycemia" = glucose in the blood). Hyperglycemia causes intense thirst, the need to urinate frequently, blurred vision, fatigue, and other symptoms. Over time, high blood glucose can cause very serious medical problems.
These problems include:
Scientists don't know exactly what causes diabetes, but it appears to result from a combination of genetics and environmental factors, including viral infections, poor diet, and sedentary lifestyle.
Currently there is no cure for diabetes but it can be managed.
Type I Or Insulin Dependent Diabetes Mellitus (IDDM)
What Is It?
People with type I diabetes do not produce insulin and need regular shots of it to keep their blood glucose levels normal. Almost half the people with this type of diabetes are age 20 and younger. That is why type I diabetes was once called juvenile-onset diabetes. However that name has been dropped because type I diabetes also strikes young adults. Type I diabetes accounts for only about 5 to 10 percent of the disease. The vast majority of diabetics have type II.
Risk Factors
What Causes It?
Genetics. Diabetes is not strictly genetic. Most children of diabetic parents do not develop the disease. However, scientists have long suspected that heredity plays a role because type I diabetes tends to run in families. A family history of the disease increases the risk. Researchers have found several genes that appear to increase the risk of type I diabetes. But they have not found a single gene that causes the disease.
Auto-antibodies. Type I diabetes has many hallmarks of an auto-immune condition. In auto-immune diseases, the immune system, which protects you from disease by killing invading germs, mistakes the body's own cells for germs and destroys them. In the case of type I diabetes, the immune system kills the cells in the pancreas that produce insulin (beta cells).
Viruses. Type I diabetes often strikes shortly after a viral infection, and doctors often notice a sharp jump in type I diabetes diagnoses after viral epidemics. Which viruses? Candidates include those that cause mumps, German measles, and a close relative of the virus that causes polio. Why would viruses cause diabetes? They do not cause it directly. Instead, these viruses contain proteins that look very similar to proteins found in the pancreas' insulin-producing beta cells. The immune system presumably mistakes the beta cells for virus particles and destroys them--along with that person's ability to synthesize insulin.
Chemicals and Drugs. Studies have shown that Pyriminil, a poison used to kill rats, can trigger type I diabetes. So can two prescription drugs--pentamidine, used to treat pneumonia, and L-asparaginase, a cancer treatment. Other chemicals have been shown to cause diabetes in animals, but scientists do not know if they would do the same in humans because it is medically unethical to test them in people. All the chemicals and drugs that cause type I diabetes do so by destroying the beta cells.
Type II Or Non-Insulin Dependent Diabetes Mellitus (NIDDM)
What Is It?
Ninety to ninety-five percent of people with diabetes have type II diabetes. Type II diabetics produce insulin, but the cells in their bodies are "insulin resistant"--they do not respond properly to the hormone, so glucose accumulates in their blood. Insulin resistance increases as weight increases and physical activity decreases. Not surprisingly, most people with type II diabetes have sedentary lifestyles, and are obese--they weigh at least 20 percent more than what is recommended for their height and build. Some people with type II diabetes must inject insulin, but most can control the disease through a combination of weight loss, exercise, and prescription oral diabetes medication.
Risk Factors
Genetics. Like type I diabetes, type II diabetes also runs in families.
Age. Nearly all people diagnosed with type II are over 30 years old. Half of all new cases are aged 55 and older.
Race/Ethnicity. Compared with whites and Asians, type II diabetes is more common among Native Americans, African Americans, and Hispanics.
Being overweight or obese. Insulin resistance increases with weight (a high-fat diet is a key cause of obesity).
Sedentary lifestyle. Insulin resistance increases with lack of exercise.
Women who have had gestational diabetes. Previous gestational diabetes increases the risk of type II diabetes in later years.
Women who have given birth to babies weighing 9 pounds or more.
What Causes It?
Like type I diabetes, type II diabetes also runs in families. This suggests that there is some type of genetic component. In fact, a genetic link seems even stronger in type II diabetes than in type I. Scientists have not yet put their finger on a single gene that causes the disease. Researchers also suspect a genetic susceptibility to obesity.
Obesity is the single most important cause of type II diabetes. Definitions of obesity differ, but in general, you're obese if you weigh at least 20 percent more than what is recommended for your height and build. Three-quarters of type II diabetics are or have been overweight. For reasons that remain unclear, carrying excess body fat somehow causes insulin resistance. That's why type II diabetes is usually treated with diet and exercise. Dropping weight and gaining muscle helps the body use insulin more efficiently. Where you carry your weight is as important as how much you carry. People who carry their fat above their hips ("apple shape") have a greater risk of developing type II diabetes than those who carry it on their hips ("pear shape").
Age also plays a role in type II diabetes. Half of all new diagnoses are in people over 55, and nearly 11 percent of Americans aged 65 to 74 have type II diabetes. However, it's not clear whether age, per se, is a cause of type II diabetes, or simply a reflection of the fact that people tend to gain weight and become less physically active as they grow older.
Gestational Diabetes
What Is It?
Gestational diabetes develops only in pregnant women with no previous history of diabetes. Nearly 135,000 women develop gestational diabetes each year. Typically, gestational diabetes clears up on its own after women have delivered their babies. But studies have shown that about 40 percent of women with gestational diabetes go on to develop type II diabetes within 15 years. All pregnant women should be tested for gestational diabetes between their 24th and 28th weeks of pregnancy.
Risk Factors
Genetics. It tends to run in families.
Obesity. Because it increases insulin resistance.
Race/Ethnicity. Hispanic Americans, Native Americans, and African Americans are at increased risk, presumably because compared with whites and Asians, they are more likely to be overweight.
What Causes It?
Hormones. Pregnant women produce various hormones essential to the baby's growth. However these hormones may also make the mother insulin resistant. All pregnant women have some degree of insulin resistance. But if this resistance becomes full-blown gestational diabetes, it usually appears around the 24th week of pregnancy. That is why all pregnant women should be screened for gestational diabetes around that time.
Genetics. Because both gestational and type II diabetes develop due to insulin resistance, researchers suspect that these two conditions have a similar genetic basis.
SYMPTOMS OF DIABETES
You are at a higher risk of developing type I if....
You're at a higher risk of developing type II diabetes if....
GLOSSARY OF TERMS
Beta cells. The cells that make insulin. They are found in the islets of Langerhans in the pancreas, a comma-shaped gland located behind the stomach.
Blood glucose. Blood sugar, the body's main fuel. In diabetics, because of insulin resistance or lack of insulin, the body cannot move blood glucose out of the bloodstream and into the cells where it is used.
Diabetes. A disease characterized by a lack of insulin production, or the body's inability to use the insulin it produces properly. In diabetes, blood glucose levels rise to abnormal levels, which can cause a host of symptoms and complications.
Gestational diabetes. A particular, transient type of diabetes triggered by pregnancy. Hormones released during pregnancy can raise the mother's blood glucose levels to diabetic levels. The mother can lower levels with diet and exercise, or she may need to inject insulin. Gestational diabetes clears up after giving birth, women who have had it are at risk for developing type II diabetes later in life.
Glucagon. A hormone produced by the pancreas that raises blood glucose levels. An injectable form can be prescribed for treating severe cases of hypoglycemia.
Glucose. Blood sugar, the form of sugar that fuels the body. Produced by digesting foods, it is carried by the blood to the cells. The amount of glucose in the blood is known as the blood glucose level.
Hyperglycemia. Dangerously high (hyper) blood glucose (glycemia), a level higher than 140 mg/dl. Acute symptoms include frequent urination, increased thirst, and weight loss. If left untreated, hyperglycemia produces chronic diabetes complications: cardiovascular disease, neuropathy, retinopathy, and nephropathy.
Hypoglycemia. Dangerously low (hypo) blood glucose (glycemia), a level lower than 70 mg/dl. Symptoms include moodiness, numbness in the arms and hands, confusion and shakiness, or dizziness. If left untreated, hypoglycemia can cause sudden loss of consciousness.
Insulin. A hormone produced by the pancreas that enables the body's cells to use glucose. It "tells" the cells to let glucose in. The cells then use glucose as fuel. In type I diabetes, the person does not produce insulin. In type II diabetes, the person produces insulin, but the body cannot use it properly.
Insulin resistance. The main problem in type II diabetes. The pancreas produces insulin, but the cells do not respond to it properly--they're resistant.
Pancreas. The comma-shaped gland behind the stomach whose beta cells produce insulin.
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