It's not easy to maintain proper glucose levels. People with type 1 diabetes need to give themselves at least three injections of insulin a day and check their blood sugars three to four times a day. They also need to incorporate proper diet and exercise.

Previous studies have linked tight blood sugar control to lower risk of clogged arteries and eye, kidney and nerve disease, said study author Dr. David Nathan, director of the Diabetes Center at Massachusetts General Hospital. Now, he said, the new findings "send a very important message" on the entire cardiovascular front.

Still, "there are substantial numbers who are not reaching the glucose levels that would benefit them," said Nathan, who presented the study Sunday at the American Diabetes Association annual meeting in San Diego.

At Least Three Insulin Injections a Day

As many as 1 million Americans have type 1 diabetes, which typically strikes children and young adults and stops the body from producing enough insulin to process blood sugar. Type 2 diabetes is much more common, affecting perhaps 17 million Americans.

Nathan and his colleagues followed 1,441 volunteers with type 1 diabetes who were enrolled in a study between 1983 and 1989. The patients were 13 to 39 years old when they took part in the study, and the researchers wanted to see if they developed heart disease as they got older, Nathan said.

Some of the patients were told to intensively control their diabetes to keep their hemoglobin A1c (HbA1c) levels as close as possible to the normal value of 6 percent or less. (According to the researchers, the levels indicate the level of sugar in the blood over the past two to three months.)

To do so, the patients had to closely monitor their blood sugar levels and give themselves at least three insulin injections a day or use an insulin pump. Normally, patients would have given themselves fewer injections.

After about six years, researchers advised both groups -- those who intensively controlled their diabetes and those who didn't -- to carefully control their blood sugar levels. Over time, the levels in both groups leveled off to about 8 percent.

Long-Lasting Reductions in Complications

Even so, the six years of being in the intensive control group in the 1980s paid off for those patients. Of 1,375 volunteers who continued to provide information to researchers, those who had intensively controlled their diabetes in the 1980s were less than half as likely as the others to have had heart attacks, strokes, angina, angioplasties or coronary bypass operations.

In general, people with type 1 diabetes have 10 times the risk of heart attack as people without diabetes.

Nathan acknowledged it's not easy to maintain proper glucose levels. "It takes some work on the part of the patient and the health-care team," he said. "For people with type 1, they need to give themselves at least three injections of insulin a day and check their blood sugars three to four times a day, and they need to incorporate proper diet and exercise."

And what of those patients who fail to take the recommended steps? "It's never too late to start," advised Dr. Stuart Weiss, an assistant professor of clinical medicine at New York University School of Medicine, especially in light of the new findings.

"Even short periods of tight control make for long-lasting reductions in complications," he said.

More information: To learn more about type 1 diabetes, try the American Diabetes Association.