Under the National Minimum Drinking Age Act of 1984, all US states are required to prohibit individuals under the age of 21 from purchasing or publicly possessing alcoholic beverages. By 1988, all US states had adopted this minimum drinking age, Medical News reports.

But in 2006, this federal law was challenged. A nonprofit organization called Choose Responsibility began campaigning for a reduction in the legal drinking age till 18-20.

In 2008, presidents of universities and colleges over the US created the Amethyst Initiative. This group called for a re-evaluation of the legal drinking age.

According to Prof. William DeJong, of Boston University School of Public Health in Massachusetts, these campaigns received a lot of media attention.

This led public health experts to carry out new studies in order to analyze the impact of the age-21 drinking law. 

Prof. DeJong and colleagues conducted a review of research where they confirm that the age-21 drinking laws have helped reduce youth binge drinking and the number of drunk-driving accidents.

From this, the investigators found that since the age-21 law was brought in, youths have been consuming less alcohol and are less likely to be involved in alcohol-related motor vehicle accidents.

The researchers point to one study conducted in 2011, which revealed that 36% of college students reported consuming five or more alcoholic beverages in the past 2  weeks.

Prof. DeJong notes that young people will consume alcohol despite the age-21 law. But he says there is clear evidence that the law is reducing the number of alcohol-related deaths in this population.

But Prof. DeJong says better education surrounding alcohol consumption may help discourage this population from underage drinking.