Insulin pumps are used by tens of thousands of teenagers worldwide with Type 1 diabetes, but they can be risky and have been linked to injuries and even deaths, a review by federal regulators in the U.S. finds.

Parents should be vigilant in watching their children's use of the pumps, researchers from the Food and Drug Administration wrote. They didn't advise against using the devices, but they called for more study to address safety concerns in teens and even younger children who use the popular pumps.

The federal review of use by young people over a decade found 13 deaths and more than 1,500 injuries connected with the pumps. At times, the devices malfunctioned, but other times, teens were careless or took risks, the study authors wrote.

Some teens didn't know how to use the pumps correctly, dropped them or didn't take good care of them. There were two possible suicide attempts by teens who gave themselves too much insulin, according to the analysis.

"The FDA takes pediatric deaths seriously," said the agency's Dr. Judith Cope, lead author of the analysis. "Parental oversight and involvement are important. Certainly teenagers don't always consider the consequences."

The pumps are popular because they allow young people to live more normal lives, giving themselves insulin discreetly in public and getting pizza with friends late at night. And they're a growing segment of diabetes care, with $1.3 billion US in annual sales worldwide, said Kelly Close, a San Francisco-based editor of a patient newsletter. She said 100,000 teenagers may be using them.

The pumps are used for those with Type 1 diabetes, which accounts for between five and 10 per cent of all diabetes cases and used to be called "juvenile diabetes." The more common form is Type 2, which is often linked to obesity and more often affects adults.

Type 1 affects an estimated 12 million to 24 million people worldwide and occurs when the body attacks insulin-producing cells in the pancreas. Insulin regulates blood sugar levels which, when too high, can lead to heart disease, blindness and kidney damage.

Insulin pumps are the size of a cellphone and worn on a belt or pocket. They send insulin into the body through a plastic tube with a small tip that inserts under the skin and is taped in place. They cost about $6,000 and supplies run $250 a month. Users must tell the device how much insulin to give before each meal, based on the estimated carbohydrates in the meal. The devices also deliver a continuous low level of insulin.

In the FDA study, appearing in the May issue of the journal Pediatrics, the reports of adverse events and deaths in adolescents using the pumps occurred from 1996 to 2005.

The FDA requires manufacturers to report injuries that could be linked to medical devices. The authors analyzed reports from patients 12 to 21 years old. They emphasized that the reports aren't always clear about the cause of death or injury.

The devices provide an alternative to multiple daily injections of insulin by syringe; some come with glucose monitors that reduce the number of times the finger must be pricked to test blood sugar.

While some teenagers want to switch from insulin injections to pump therapy to gain more flexibility in their lives, doctors said device problems such as a blocked tube can lead quickly to dangerous episodes of high blood sugar.

"In a matter of a few hours, all the insulin in the body disappears," said Dr. John Buse, the American Diabetes Association's president for medicine and science. "Metabolically, the child starts to spiral out of control.

"Kids need to be aware of the risk, monitor their blood sugar and be ready to give themselves an insulin injection."