People who grew up in states where it was legal to drink alcohol before age 21 are more likely to be binge drinkers later in life, according to a study by researchers at Washington University School of Medicine in St. Louis.

The findings are available online in Alcoholism: Clinical & Experimental Research.

The researchers tracked the long-term drinking behavior of more than 39,000 people who began consuming alcohol in the 1970s, when some states had legal drinking ages as low as 18.

“It wasn’t just that lower minimum drinking ages had a negative impact on people when they were young,” explains first author Andrew D. Plunk, PhD, a post-doctoral research fellow in psychiatry. “Even decades later, the ability to legally purchase alcohol before age 21 was associated with more frequent binge drinking.”

The study shows that people who lived in states with lower minimum drinking ages weren’t more likely to consume more alcohol overall or to drink more frequently than those from states where the drinking age was 21, but when they did drink, they were more likely to drink heavily.

The effect was most pronounced among men who did not attend college. And the researchers say the findings should be a warning to those who advocate lowering the minimum drinking age.

“Binge drinking on college campuses is a very serious problem,” Plunk says. “But it’s also important not to completely forget about young people who aren’t on college campuses. In our study, they had the greatest risk of suffering the long-term consequences linked to lower drinking ages.”

Plunk and his colleagues found that even decades later, men who grew up in states with a legal drinking age lower than 21 were 19 percent more likely to binge drink more than once per month. Among those who didn’t go to college, the odds of binging more than once a month increased by 31 percent.

Through surveys conducted in the early 1990s and again in the early 2000s, the researchers tracked the average daily alcohol intake, overall drinking frequency and the frequency of binge episodes — defined as five or more drinks during a single period of drinking for a man or four-plus drinks for a woman. They also looked at how often a person drank but did not binge, which is thought to be a less harmful drinking pattern.

“There’s a difference between tracking average daily consumption of alcohol and measuring drinking patterns,” explains senior author Richard A. Grucza, PhD, an associate professor of psychiatry. “Merely tracking average daily consumption can hide harmful drinking patterns. Averaging one drink per day doesn’t sound like much, but if that same person has all their drinks for the week in one sitting, well that’s a potential problem.”

Due to concerns about binge drinking on college campuses, some policymakers think that lowering the drinking age may encourage college students to moderate their alcohol use.

“The ‘take away message’ is that we need to consider all of the potential consequences of changing the drinking age,” Plunk explains. “We shouldn’t be too narrow in our focus when we think about how young people are affected by these laws. This study shows there’s a large population that benefitted from a higher legal drinking age. Laws apply to everyone, but if they are based only on the impact on one group like college students, we may end up forgetting about how those laws affect other people.”

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Plunk AD, Cavazos-Rehg P, Bierut LJ, Grucza RA. The persistent effects of minimum drinking age laws on drinking patterns later in life. Alcoholism: Clinical & Experimental Research, vol. 37 (3), March 2013

Funding for this research comes from the National Institute on Drug Abuse (NIDA) and the National Institute on Alcohol Abuse and Alcoholism, (NIAAA) of the National Institutes of Health (NIH). NIH grant numbers are T32-DA07313, R21-DA0266, R01-DA031288 and K02-DA021237.

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By Jim Dryden