Women with type 1 diabetes who cut back on insulin to prevent weight gain face a threefold higher risk of dying early in life, a study reports today.

The study highlights the risk involved in restricting insulin, a practice that often goes hand in hand with an eating disorder, says Ann Goebel-Fabbri, a psychologist at the Joslin Diabetes Center in Boston. Some type 1 diabetics, especially young women, cut back on insulin and then use other strategies such as fasting to stay thin.

Goebel-Fabbri and her colleagues studied 234 women and teens with type 1 diabetes, a disease in which the immune system destroys the cells in the pancreas that make insulin.

Type 1 diabetics must receive a daily injection of insulin, a hormone that helps the body use sugar as fuel.

At the beginning of the study, the researchers found that 30% of the women were restricting the amount of insulin they took at least some of the time. The team kept track of the women for 11 years and noted any deaths or complications from their disease.

The team found that women who reported cutting back on insulin had higher rates of complications such as foot problems or kidney disease, which can be life-threatening. Without enough insulin, sugar builds up in the blood and starts to damage many parts of the body.

The team also noted that women who cut down on insulin were more likely to die young: Women who restricted insulin died on average at age 45. Women who used insulin appropriately lived to an average age of 58, says the study in the March issue of Diabetes Care.

Women who skipped insulin shots and then died during the study also had more symptoms of eating disorders, including bulimia, the practice of eating large quantities of food and then vomiting.

Insulin restriction adds to that strategy: Without enough insulin, the body excretes extra sugar in the blood. Diabetics who skip insulin shots can eat more and still not gain weight, Goebel-Fabbri says.

"This is a dramatic and very dangerous way to purge calories from the body," Goebel-Fabbri says.

Other studies have shown that women who have diabetes are 2 1/2 times more likely to develop an eating disorder than women who don't. Diabetes is a disease that involves constant attention to calories, which might trigger a preoccupation with body image and the desire to remain thin, Goebel-Fabbri says.

Not every diabetic who skips a dose of insulin has an eating disorder, cautions Paul Strumph, chief medical officer for the Juvenile Diabetes Research Foundation in New York. He says some diabetics may have trouble following a complex regimen that might involve many shots of insulin every day.

But doctors should be alert to the possibility of an eating disorder, especially in young women who might not acknowledge the problem, Goebel-Fabbri says.

"What happens is people can get stuck in a cycle of shame, and that can be a barrier to getting treatment," she says.

Doctors who suspect a problem should refer patients to a therapist who is trained to deal with eating disorders, Goebel-Fabbri says. Prompt treatment might help patients stop the risky behavior before they develop potentially lethal complications, she says.