OPM has told FEHB carriers to bring their coverage for obesity treatments in line with the most recent medical research, the latest in an ongoing series of steps aimed at reducing the health risks associated with obesity. OPM noted that it previously has emphasized diet, exercise and nutrition programs as well as coverage for certain drugs. The new letter notes the connection between obesity and various health conditions — diabetes in particular — and cites developments in the area of bariatric surgery. It said the latest standards "strongly support" authorizing such surgery for patients with certain body mass index ratios, varying according to whether the individual also has obesity related health conditions. It told plans to clearly state their requirements for authorizing such surgery, including any waiting periods, and recommended that they refer enrollees who qualify to certain specialized centers accredited by the government. In addition, it encouraged plans to refer enrollees who do not meet standard criteria to participate in clinical trials.