http://www.msnbc.msn.com/id/23579662/ 6th grade? A significant number of children are already drinking by middle school, suggesting that prevention needs to start in the elementary grades, researchers conclude in a new report. In their study of more than 4,000 sixth-graders at Chicago schools, 17 percent of the children had used alcohol in the past year. Those students who'd started drinking were also more likely than their peers to have a range of problems, such as getting into fights, shoplifting or getting into trouble at school. The findings, reported in the journal Health Education and Behavior, suggest that alcohol prevention needs to start in grade school, researchers say.