Diabetes Types
Type 1 Diabetes Defined
People with type 1 diabetes (also called insulin-dependent diabetes mellitus or IDDM) don't produce insulin and need regular shots of it to keep their blood glucose levels normal. Type 1 diabetes was once called juvenile-onset diabetes, but that name has been dropped because type 1 diabetes strikes young and older adults alike. Type 1 diabetes accounts for about 5% to 10% of those who have the disease.
Risk Factors
- Your genes. A family history of the disease increases risk.
- Your ethnic background. Diabetes happens in people of every race, but it's most common among whites.
- Your age. Half of those diagnosed with type 1 are under 20. Being age 20 or younger increases your risk.
What Causes It?
Most children of parents with diabetes do not develop the disease. However, scientists have long suspected that heredity plays a role because type 1 diabetes tends to run in families. Researchers have identified several genes that appear to increase risk of type 1 diabetes. But they haven't yet found a single gene that causes the disease.
Auto-Antibodies
Type 1 diabetes has many hallmarks of an autoimmune condition. In autoimmune 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 1 diabetes, the immune system kills the cells in the pancreas that produce insulin (beta cells).
Viruses
Type 1 diabetes often strikes shortly after a viral infection, and doctors sometimes notice a sharp jump in type 1 diabetes diagnoses after viral epidemics. Viral candidates include those that cause mumps, German measles, and a close relative of the virus that causes polio. Why would viruses cause diabetes? They don't cause it directly. Instead, these viruses contain proteins that look very similar to proteins found in the pancreas's insulin-producing beta cells. The immune system presumably mistakes the beta cells for virus particles and destroys them -- along with the body's ability to make insulin.
Chemicals and Drugs
Studies show that ingestion of Pyriminil, a poison used to kill rats, can trigger type 1 diabetes. So can the prescription drug pentamidine, used to treat pneumonia. Other chemicals cause diabetes in animals, but scientists don't know if they would do the same in humans.
Cow's Milk
Some studies suggest that exposure to cow's milk during infancy may increase risk of type 1 diabetes. Cow's milk contains a protein similar to a protein found on beta cells. The theory is that if infants develop antibodies to the cow's milk protein; their immune system may mistake the beta cells for milk and destroy them.
The cow's-milk connection has always been controversial, and it recently became more so when a well-designed study by University of Colorado researchers showed no link between cows milk exposure in infancy and increased risk of type 1 diabetes. However, even a remote chance that cow's milk might increase risk of diabetes strengthens the case for breastfeeding.
Type 2 Diabetes Defined
Ninety percent to 95% of people with diabetes have type 2 disease (also called non-insulin-dependent diabetes mellitus or NIDDM). Those with type 2 produce insulin, but the cells in their bodies are "insulin resistant" -- they don't respond properly to the hormone, so glucose accumulates in their blood. Some people with type 2 diabetes must inject insulin, but most can control the disease through a combination of weight loss, exercise, a prescription oral diabetes medication, and tight control.
Risk Factors
- Your genes. Like type 1 diabetes, type 2 disease also runs in families.
- Your ethnic background. Compared with caucasians and Asians, type 2 diabetes is more common among Native Americans, African-Americans, Latinos, and Hispanics.
- Being overweight or obese. Insulin resistance worsens as weight increases and physical activity decreases. Many people with type 2 diabetes have sedentary lifestyles and are obese; they weigh at least 20% more than the recommended weight for their height and build.
- Leading a sedentary lifestyle. Lack of exercise, especially in those who are overweight, increases risk.
- A history of gestational diabetes. If you developed gestational diabetes during pregnancy, you're at a higher risk of type 2 diabetes later.
- Birthing a large baby. Women who have given birth to babies weighing 9 pounds or more are at an increased risk.
- Using certain drugs. These include thiazide diuretics (used to manage high blood pressure) and steroids (used to help with inflammatory conditions).
What Causes It?
Scientists are not certain, but type 2, like type 1 diabetes, runs in families, which suggests some genetic connection. In fact, a genetic link seems even stronger in type 2 diabetes than in type 1. Scientists have not yet put their finger on a single gene that causes the disease, but they are finding errors in several that may contribute to the disease. Researchers also suspect a genetic susceptibility to obesity.
Obesity is the single most important cause of type 2 diabetes. Definitions of obesity differ, but in general, you're obese if you weigh at least 20% more than what's recommended for your height and build. Three-quarters of people with type 2 diabetes are overweight. For reasons that remain unclear, carrying excess body fat somehow causes insulin resistance. That's why type 2 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 2 diabetes than those who carry it on their hips ("pear shape").
Age also plays a role in type 2 diabetes. Half of all new diagnoses are in people age 55 and up, and nearly 11% of Americans ages 65 to 74 have type 2 diabetes. However, researchers don't know if age is a cause of type 2 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 Defined
Gestational diabetes develops only in pregnant women with no previous history of diabetes. Nearly 135,000 U.S. women develop gestational diabetes each year.
Typically, gestational diabetes clears up on its own after women have delivered their babies. But studies show that about 40% of women with gestational diabetes go on to develop type 2 diabetes within 15 years. All pregnant women should be tested for gestational diabetes between their 24th and 28th weeks of pregnancy.
Keeping your weight down, eating healthfully, and exercising regularly during pregnancy may help prevent insulin resistance and gestational diabetes.
Risk Factors
- Your genes. Diabetes tends to run in families.
- Being overweight or obese. Too many pounds increase insulin resistance.
- Your ethnic background. Native Americans, African-Americans, and people of Hispanic or Latino descent are at increased risk. Caucasians and Asians have a lower risk.
What Causes It?
Hormones may play a role. Pregnant women produce various hormones essential to their baby's growth. However, these hormones may interfere with the mother's body's ability to properly use insulin, causing insulin resistance.
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's why all pregnant women should be screened for gestational diabetes around that time.
Complications Caused By Diabetes
You need to know that unchecked diabetes can lead to serious conditions. These include:
Heart disease, stroke, and blood-vessel (cardiovascular) diseases. Cardiovascular disease is by far the leading cause of death in the United States, but people with diabetes are at much higher risk.
Kidney disease. Also called nephropathy, this complication happens when the kidney's "filter mechanism" is damaged and protein leaks into urine in excessive amounts and eventually the kidney fails.
Eye diseases. Diabetes is a leading cause of damage to the retina at the back of the eye and also increases risk of cataracts and glaucoma.
Nervous-system problems. Nerve damage, especially in the legs and feet, may interfere with the ability to sense pain and contributes to serious infections.
Loss of Libido. Nerve damage in the penis brought on by diabetes has shown to yield total loss of erectile function.
Unfortunately, adding up the total toll of diabetes complications shows the disease is one of the nation's leading causes of death.
But don't despair. All diabetes complications can be largely prevented by practicing what is known as "tight control," keeping your blood glucose level as close to normal as possible. This takes time and energy, but many people with diabetes do it successfully and live full lives without much trouble.
