FRIDAY, Feb. 3 (HealthDay News) -- People who start using hard drugs -- such as cocaine, opiates and amphetamines -- as young adults and continue to use them into their 50s have a fivefold increased risk of early death, researchers report.

The finding is from an analysis of hard drug use among 4,300 U.S. adults who took part in a long-term study of cardiovascular disease and risk factors. The participants, including blacks, whites, men and women, were recruited when they were 18 to 30 years of age and followed from 1985 to 2006.

The University of Alabama at Birmingham researchers compared those who stopped drug use early in life to those who continued, and calculated their risk of premature death.

"Fourteen percent of the people in the study reported recent hard-drug use at least once, and of these, half continued using well into middle age," lead author Dr. Stefan Kertesz, an associate professor in the preventive medicine division, said in a university news release.

Kertesz characterized most drug users as "dabblers" who used a few days a month, but not daily.

The researchers found that older drug users were more likely to have been raised in economically challenging circumstances in a family that was unsupportive, abusive or neglectful.

Those who were heavy drug users when they were young adults and continued into middle age were about five times more likely to die prematurely than people who didn't use drugs, according to the report published online Jan. 27 in the Journal of General Internal Medicine.

But, while the study uncovered an association between continued heavy drug use and premature death, it did not prove a cause-and-effect relationship, the study authors noted.

"We can't assume that drugs caused death, as in an overdose," Kertesz said. "Rather what we found is that middle-age adults who continue to dabble in hard drugs represent a group that is at risk of bad outcomes -- which could include death from trauma, heart disease or other causes that are not a direct result of their drug use -- at a higher rate than people who stopped using drugs."

About 9.4 percent of Americans aged 50 to 59 and 7 percent of those aged 35 to 49 reported use of a drug other than marijuana sometime in the past year, according to the U.S. National Survey on Drug Use and Health.

More information

The U.S. Substance Abuse and Mental Health Services Administration has more about illicit drug use among older adults.