Cari Lightner’s legacy may be more far reaching than anyone thought. She was the 13-year-old girl whose death in 1980 caused by a hit-and-run drunk driver spurred her mother, Candace Lightner, to create Mothers Against Drunk Driving (MADD). Candace Lightner’s personal crusade was so successful that only two years after Cari’s death, Lightner was invited by President Ronald Reagan to be a member of the presidential commission that subsequently recommended the minimum legal drinking age (MLDA) be raised to 21.

The National Minimum Drinking Age Act of 1984 legislated the withholding of revenue from states that allow the purchase of alcohol by anyone under the age of 21; by 1987, all 50 states had set their MLDA at 21.

Now, more than 30 years after Lightner founded MADD, proponents say that alcohol-related traffic fatalities in the United States have been cut by 40 percent, and they estimate that MADD and its efforts have saved more than 300,000 lives.

But researchers at the Washington University School of Medicine in St. Louis, in a November 15, 2011, online article in Alcoholism: Clinical and Experimental Research, have chronicled another possible result of the change in MLDA that may have added substantially to the number of lives saved: A lower MLDA appears to be associated with a persistent, elevated risk for suicide and homicide among women. These researchers said their data suggest that the national MLDA of 21 may be preventing as many as 600 suicides and 600 homicides annually in the United States.

Their findings are based on an analysis of data from the U.S. Multiple Cause of Death files, 1990 to 2004, combined with data on the living population from the U.S. Census and American Community Survey.

Richard Grucza, Ph.D., M.P.E., an assistant professor of psychiatry at Washington University in St. Louis, and colleagues found that women who grew up during a time of lower drinking-age laws in some states, particularly women born after 1960, were at higher risk for taking their own life or that of someone else. The databases the researchers examined included records on more than 200,000 suicides and 130,000 homicides for individuals born from 1949 to 1972, who reached adulthood during years when the drinking age was in flux in many states.

Why women but not men? “The sex specificity of the MLDA-suicide and MLDA-homicide associations may be related to unique alcohol-related risks faced by women,” wrote Grucza and colleagues. They also theorized that although suicide attempts are more common in women but completions are more prevalent in men, alcohol problems stemming from lower MLDAs may increase the lethality of suicide attempts by women, as well as elevate rates of partner violence and influence rates of female homicide deaths.

They also speculated that the reason suicide and homicide rates were not associated with MLDA for women born prior to 1960 may be that “excessive drinking was simply not part of the culture for women born in earlier years of the cohorts examined here, and changing cultural norms may be a key contributor to MLDA-associated suicide and homicide risk observed for more recent birth years.”

Could other factors be involved? “Because we were working with vital-statistics data, there were a limited number of additional factors that could be explicitly modeled, although education was one of them, and it did not influence the association,” Grucza explained to Psychiatric News. “Unless other factors changed at the same times and in the same places as drinking-age laws, they are unlikely to account for the association we saw between MLDA and suicide/homicide.”

The study was supported by grants from the National Institutes of Health.

An abstract of “The Legacy of Minimum Legal Drinking Age Law Changes: Long-Term Effects on Suicide and Homicide Deaths Among Women” is posted at http://onlinelibrary.wiley.com/doi/10.1111/j.1530-0277.2011.01608.x/abstract.