People with type 1 diabetes live almost as long as other Americans, a new study finds. In this disease, the immune system attacks the body. It destroys cells in the pancreas that make insulin. People need to replace this insulin by injection multiple times a day. The study included 390 people who were diagnosed with type 1 between 1950 and 1964. They were compared with a younger group. This group was diagnosed between 1965 and 1980. Researchers kept track of both groups for several decades. For the first group, the average life expectancy was 53.4. But this has improved for the group diagnosed later. Their average life expectancy is now 68.8, the study found. That's less than 4 years below average. U.S. life expectancy is 72.4 for people born between 1965 and 1980. Better diabetes care has narrowed the gap, researchers said. They described study results June 26 at the annual conference of the American Diabetes Association. HealthDay News wrote about it.

By Howard LeWine, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

The longer life expectancy for people with type 1 diabetes should be counted as one of the major successes of modern medicine. Less than 100 years ago, this was a deadly disease. Type 1 diabetes is an autoimmune disease. The body's immune system attacks the special cells in the pancreas that make insulin. Without insulin, you can't survive.

In 1922, a crude insulin extract was injected into a 14-year-old boy dying from diabetic ketoacidosis. This is a dangerous problem caused by a lack of insulin to move blood sugar into cells. Therefore, he could not use blood sugar for energy. To compensate, his body had to break down fats to create energy. But doing this on a large scale releases huge amounts of acid. His body stopped being able to buffer the acids to maintain a life-sustaining balance. Without the injection, he would have died within a few days.

The crude extract caused a severe allergic reaction. But the insulin kept him alive long enough for his doctors to purify the extract. Twelve days later, they gave him a second injection of the more purified insulin. There was no allergic reaction and the boy lived.

The first insulin products approved for wide commercial use were made from ground-up animal pancreas. They were much purer than the first extracts given to save the boy in 1922. But they were not exactly the same as pure human insulin. For this reason, they would occasionally cause allergic reactions.

Today, insulin for injection is made by genetic engineering. It is exactly the same as human insulin. Allergic reactions are no longer an issue.

Medical research has been very successful in finding better ways to prevent other complications of type 1 diabetes that cause disability and early death. Now life expectancy for an American with type 1 diabetes is close to the national average.

What Changes Can I Make Now?

Keeping blood sugars as close to normal as possible is the primary goal when type 1 diabetes is first diagnosed. After that, achieving other goals can help prevent further health problems related to diabetes.

High blood sugar does particular harm to certain parts of the body:

• Eyes -- Damage to the back of the eye is called diabetic retinopathy. This was much more common in the past. More people now realize how important it is to control blood sugar. So new cases of blindness caused by diabetes are falling steadily.
• Nerves -- Persistently high blood sugars cause peripheral neuropathy. Numbness, tingling and/or pain occur in the feet and can move up the legs. It can also involve the hands. With decreased sensation, foot injuries are more likely to occur.
• Small blood vessels -- The damage to small blood vessels affects many organs, especially the kidney. It also delays wound healing. Minor skin injuries can remain open. This can lead to serious infections.

If you have diabetes, you are more likely to develop coronary heart disease and heart failure. So you have even more reason to control other factors that increase the risk of heart disease.

• Don't smoke.
• Keep blood pressure normal, ideally below 130/80.
• Strive for an LDL cholesterol of less than 100 milligrams per deciliter (mg/dL). Ideally, keep it closer to 70 mg/dL.

What Can I Expect Looking to the Future?

Until recently, no one would have predicted that people with type 1 diabetes could have a nearly normal life span. In fact, some people are now living into their 80s. A few have reached 90.

Researchers are busy looking to find out what these people did right.