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.