ATLANTA (AP) -- Drug-related deaths outnumber those from motor vehicle accidents in a growing number of states, according to new government data that highlight a shift in the top cause of deaths after disease and illness.

Crashes still cost more lives nationwide, but state-by-state calculations show the rate of drug-induced deaths outpaced vehicle accidents in 16 states in 2006, up from about a dozen states the year before and eight in 2003.

Drug overdoses make up the vast majority of the drug-related deaths, and there was a sharp increase in fatalities tied to cocaine and to drugs known as opioid analgesics -- including methadone, fentanyl, sedatives and prescription painkillers like Vicodin and OxyContin.

From 1999 to 2006, death rates for opioid analgesics increased for every age group. Deaths from methadone alone increased sevenfold, the U.S. Centers for Disease Control and Prevention said in a report released Wednesday.

Based on death certificate data, CDC researchers counted more than 45,000 U.S. deaths from motor-vehicle crashes in 2006, and about 39,000 from drug-induced causes. The CDC does not have finalized data for 2007 or subsequent years.

About 90 percent of those drug fatalities are sudden deaths from overdoses, but the count includes people who died from organ damage from long-term drug use or abuse.

The 2006 death counts and death rates were higher for drugs than for vehicle accidents in Massachusetts, New Hampshire, Rhode Island, Connecticut, New York, New Jersey, Maryland, Pennsylvania, Ohio, Michigan, Illinois, Colorado, Utah, Nevada, Oregon and Washington.

It's not clear why certain states have seen such a shift. There are probably a variety of reasons, and the explanation may vary a bit from state to state, said Bob Anderson, chief of the mortality statistics branch at the CDC's National Center for Health Statistics.

Part of the story is that traffic death rates are going down. The death rate for people killed in motor vehicle crashes decreased by about 6.5 percent from 1999 through 2006 -- from 15.3 per 100,000 to 14.3 per 100,000, according to National Highway Traffic Safety Administration data.

Declines in motor vehicle fatalities "are considered one of the great public health triumphs" of the last few decades, said Margaret Warner, an epidemiologist who co-authored the new CDC report.

"But (drug) poisonings are definitely going up," she added.

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