A University of Maine study said Friday the medical costs of obesity for children and adolescents in the state could reach $1.2 billion over the next 20 years. University of Maine economics Professor Todd Gabe’s study also suggested that the incidence of obesity is likely to increase from 7.8 percent of Maine’s youths to nearly 26 percent as they grow into adults. Gabe said his study enlightens the public on the issue of a nationwide obesity epidemic. Last year, the medical costs of obesity for all age groups in Maine were nearly $453 million. The study uses statistics from the national Centers for Disease Control and Prevention (CDC) and data on more than 2,000 school-aged children in Maine compiled by physical education teachers in 18 schools across the state.