FRIDAY, Sept. 18 (HealthDay News) -- People who grew up in a place and time when they could legally buy alcohol before age 21 are more likely than others to be alcoholics or have a drug problem, even well into adulthood, new research shows.
"The effect lingers," said study author Dr. Karen Norberg, a research instructor in psychiatry at Washington University in St. Louis. "A drinking-age law of 21 is associated with lower risks of long-term problems with alcohol use."
The study is published online Sept. 18 in the journal Alcoholism: Clinical and Experimental Research.
Norberg and her research colleagues analyzed surveys of nearly 34,000 people born in the United States between 1948 and 1970, examining their records to determine if rates of alcoholism and drug abuse differed depending on their states' liquor-buying laws at the time the participants were teens or young adults.
In the early 1970s, 26 states lowered the drinking age to 18 after the federal voting age was lowered to 18, Norberg said. After passage in 1984 of the National Minimum Drinking Age Act, the federal government pressured states to increase the drinking age or forfeit highway funds.
By the late 1980s, most states had complied, raising the drinking age back to 21. Louisiana, the researchers noted, was the last to do so, in 1995.
In the study, people who had been allowed to buy liquor legally before age 21 were 33 percent more likely to have suffered from alcoholism in the year before they were surveyed.
Drinking at a younger age also was found to increase the risk of abusing other drugs. Those allowed to drink legally before age 21 were 70 percent more likely to have had a problem with drugs than were those who had to wait until 21 to drink legally, the study found.
No differences were detected between men and women, various ethnicities or age groups.
The findings suggest, Norberg said, that the frequency or intensity of drinking in late adolescence has long-term effects.
A study released earlier this year reported that states that allow the suspension of a driver's license for any underage alcohol violation and states with zero-tolerance laws that make it illegal for young people to drive with any level of alcohol in their system have fewer drunk-driving accidents.
So-called use-and-lose laws resulted in 5 percent fewer auto accidents related to drinking, the study found. It, too, was published in Alcoholism: Clinical and Experimental Research.
Norberg's study is believed to be the first to look at the very long-term effects of lowered drinking ages.
The study "substantiates something that has not been substantiated this way before -- that the [legal] drinking age really has long-term impact," said Dr. Marc Galanter, director of the division of alcoholism and drug abuse at New York University School of Medicine. "Even in [people's] 40s and 50s, this impact was felt."
Though people nationwide continue to debate what the ideal legal drinking age should be, with some again calling for a lower age, Galanter said the results suggest that keeping the status quo would be good.
Traci Toomey, an associate professor of public health at the University of Minnesota, who also has researched the topic, agreed. The new study, she said, provides "another piece of the puzzle that looks at the policy from another angle."