MILWAUKEE — Continuing a trend that began more than a decade ago, 16,651 people died of overdoses involving prescription narcotic painkillers in 2010, the most recent year that data were available, according to researchers with the U.S. Centers for Disease Control and Prevention.

In 1999, there were 4,030 such deaths involving opioids.

“This analysis confirms the predominant role opioid analgesics play in pharmaceutical overdose deaths, either alone or in combination with other drugs,” CDC researchers wrote in a report in JAMA, the Journal of the American Medical Association.