PARIS (AFP) - Researchers in the United States said on Tuesday they had found a shocking association if only a statistical one between violence by teenagers and the amount of soda they drank. High-school students in inner-city Boston who consumed more than five cans of non-diet, fizzy soft drinks every week were between nine and 15-percent likelier to engage in an aggressive act compared with counterparts who drank less. What we found was that there was a strong relationship between how many soft drinks that these inner-city kids consumed and how violent they were, not only in violence against peers but also violence in dating relationships, against siblings, said David Hemenway, a professor at the Harvard School of Public Health. It was shocking to us when we saw how clear the relationship was, he told AFP in an interview. But he stressed that only further work would confirm or disprove the key question whether higher consumption of sweet sodas caused violent behaviour. The new study was based on answers to questionnaires filled out by 1,878 public-school students aged 14 to 18 in the inner Boston area, where Hemenway said crime rates were much higher than in the wealthier suburbs. The overwhelming majority of respondents were Hispanic, African-American or mixed; few were Asian or white. Among the questions were how much carbonated non-diet soft drink, measured in 12-ounce (355-millilitre) cans, the teens had drunk in the previous seven days. They were also asked whether they drank alcohol or smoked, carried a weapon or showed violence towards peers, family members and partner. What emerged, said Hemenway, was evidence of dose response, in other words, the more soda was consumed, the likelier the tendency towards violence. Among those who drank one or no cans of soft drink a week, 23 percent carried a gun or a knife; 15 percent perpetrated violence towards a partner; and 35 percent had been violent towards peers.