21 drinking age laws in US states are effective, multiple studies indicate

Sometimes research findings are mixed, so they can be, and often are, used to support competing policy positions. But sometimes research findings are so crystal clear that there’s not much room for dissension. This is true when it comes to the minimum age for legally purchasing alcohol, often referred to as the drinking age.

Study after study published in scientific journals since the 1970s indicates that when this age is lowered, more people die in crashes. When it’s raised, the deaths go down. These are the conclusions of a new review by Institute researchers. Similar reviews have been conducted by the Centers for Disease Control and Prevention, National Academy of Sciences, and others. The reviewed studies aren’t confined to the United States. They cover various age groups over various periods of time, with remarkably consistent results.

“The public health benefits of a 21 drinking age are as clear as they possibly can be. People younger than 21 do still drink and then get behind the wheel, but fewer are doing this and we’d worsen the problem, not alleviate it, if we lower the age and make it easier for young people to obtain the very substance that’s causing the problem in the first place,” says Anne McCartt, Institute senior vice president for research and the review’s lead author.

Underage drinking: The studies McCartt collected cover the effects of drinking age policies on patterns of behavior including not only drinking and driving but also alcohol consumption, relying in large part on a University of Michigan survey that has been tracking consumption among high school students and young adults since the 1970s. Drinking by people in these age groups has declined since the late 1970s, and most of the decline occurred by the early 1990s. These were the years when states were establishing, or reinstating, 21 drinking ages. Binge drinking, defined as consuming at least 5 drinks on 1 occasion, peaked in the early 1980s among 18-20 year-olds and then began declining as most states adopted 21 policies. Similar declines weren’t noted among 21-22 year-olds, who weren’t affected by the policy changes. High school seniors in states that still had drinking ages of 18 in 1976-81 said they drank more than peers in states that already had adopted 21. All states adopted 21 by 1988. Researchers concluded that drinking age policies were significant predictors of alcohol consumption. This is timely in light of the Amethyst Initiative (see accompanying story), which flatly states that “[t]wenty-one is not working” and wants to rethink it in light of the “culture of binge drinking.” The University of Michigan survey results indicate otherwise, suggesting that 21 policies reduce alcohol consumption.

Drinking and driving: National roadside breath surveys of nighttime drivers on weekends reveal a 74 percent decline in driving with blood alcohol concentrations (BACs) of 0.05 percent or more among people younger than 21 during 1973-96. This is a much bigger decline than in older age groups, which weren’t affected when drinking age laws were changed during the 1970-80s.

Crash deaths: The major benefit of raising the drinking age has been to prevent deaths in motor vehicle crashes. Among fatally injured drivers 16-20 years old, the percentage with positive BACs declined from 61 in 1982 to 31 in 1995. This was a bigger decline than in older age groups. Even more persuasive evidence of the benefits of 21 is supplied by studies designed specifically to gauge the effects of drinking age changes among states. For example, a 1975 Institute study showed that  lowering the drinking age to 18 in 2 US states and a Canadian province increased fatal crashes among drivers younger than 21, compared with adjacent states where drinking ages weren’t changed. Conversely, studies published by the Institute and others in 1983 found reductions in crashes among young drivers who were affected by states’ reinstatement of 21. A wealth of studies since then confirms the lifesaving benefits of 21 as the minimum drinking age. For example, in 1999 New Zealand lowered the drinking age from 20 to 18. A study published during 2006 reported that crash injury rates among 18-19 year-old boys were 12 percent higher than expected after the policy change, based on comparisons with 20-24 year-olds. The relative increase was even larger for 18-19 year-old girls, at 51 percent,
and higher injury rates also were observed for 15-17 year-olds.

Reviews yield consistent findings: Besides the Institute’s new review of drinking age studies, there’s a 2001 report from the Centers for Disease Control and Prevention that collected the findings of 33 studies and reported 10 to 16 percent changes in outcomes for drivers 18-20 years old in crashes involving alcohol. Crashes increased when drinking ages were lowered and declined  when the ages went up. The effects were consistent during follow-up time periods ranging from 7 months to 9 years. More evidence comes from a review of 57 studies by University of Minnesota researchers. This review, published in 2002, found older drinking ages associated with lower crash rates. “It’s crystal clear,“ McCartt says. “Lowering the drinking age costs lives. Raising it saves lives. Too many scientific studies with too many consistent findings have been published to conclude otherwise.” The National Highway Traffic Safety Administration agrees, reporting earlier this year that adopting 21 policies in every state has saved more than 26,000 lives since the mid-1970s, including 4,441 lives during the past 5 years. This finding is based on studies that found an average reduction of 13 percent in fatal crashes involving drivers 18-20 years old when drinking ages were raised. For a copy of “Effects of 21 minimum legal drinking age laws on alcohol-related driving in the United States” by A.T. McCartt et al., write: Publications, Insurance Institute for Highway Safety, 1005 N. Glebe Rd., Arlington VA 22201, or email publications@iihs.org.

Source:  http://www.iihs.org, Status Report, Vol. 43, No. 11, Dec. 27, 2008
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