The Food and Drug Administration expanded the approval of weight loss drug Zepbound to treat obstructive sleep apnea in adults with obesity, the drugmaker Eli Lilly said Friday. The decision makes it the first drug treatment for the disorder, which affects about 39 million adults in the United States.

Zepbound, which shares the same active ingredient as Lilly’s diabetes drug Mounjaro, is already approved by the FDA to treat adults who are overweight or have obesity.

The expanded approval…