High school students who drink a lot of soda pop are also more likely to be violent, according to a study of surveys completed in 2008 by more than 1,800 Boston high school students. The study, released late Monday in the British medical journal Injury Prevention, does not suggest a cause and effect -- only an association between soda consumption and violence.

It is possible – even likely, researchers say – that other social or biological factors make teens who are prone to violence also prone to drinking a lot of soda. Maybe poor parenting or low-blood sugar are the catalysts that make students pursue both bad habits.

Even without proving cause and effect, the study makes a meaningful contribution because there has been little focus on this connection between soda consumption and violence before. The surveys asked students how much non-diet carbonated soda they had consumed in the prior week, and whether they had carried a weapon or been violent to classmates, boy/girlfriends or relatives in the past year. Perhaps soda consumption is simply a red flag that schools and parents can monitor for a higher likelihood of violent behavior.

"If we want to understand youth violence and we want to reduce it, then we want to look at everything that can impact it," said Sara Solnick, the chairwoman of the University of Vermont's economic department who co-authored the Boston student study. "This was something that was not on the radar. Maybe we need to start paying attention."

The following table, excerpted from the study, shows the relationship. Anything with *** indicates a strong statistical relationship between the amount of soda consumed and the behavior or demographic that is compared.

Note that students who drank a lot of soda also drank more alcohol and smoked. Those are behaviors that are strongly correlated with youth violence. However, even when the latest study factored out tobacco and alcohol use, there still was a strong relationship between heavy soda consumption and a higher rate of self-reported violence.

Researchers at the University of Minnesota (not involved with the study) urged great caution in interpreting the results, and certainly discouraged anyone from believing soda causes aggression at this point. The U's Simone French noted it can't simply be the sugar in soda that agitates teens and makes them more violent.

"Using this logic, Halloween, a socially supported sugar-overdose, should cause an increase in violent behaviors among adolescents across the country," she said.

More on this study in tomorrow's Star Tribune, including a Minnesota twist to the research.