NEW YORK (AP) — U.S. health officials have updated a tool to track rising cases of severe obesity among children who were previously off the charts. Expanded growth charts released Thursday by the Centers for Disease Control and Prevention now include a body mass index of 60 — up from previous charts that stopped at a BMI of 37. They also expanded additional measures to map severe obesity, which affects an estimated 4.5 million children and teens in the U.S. Rates of severe obesity among kids have nearly quadrupled in recent decades. The CDC charts are the most widely used tool in the U.S. to track growth and development in kids.