A popular obesity drug may help treat a dangerous disorder in which people struggle to breathe while they sleep, a new study finds.

Tirzepatide, the medication in the weight loss drug Zepbound and also the diabetes treatment Mounjaro, appeared to reduce the severity of sleep apnea along with reducing weight and improving blood pressure and other health measures in patients with obesity who took the drug for a year.

Eli Lilly and Co., the drug’s maker who paid for the research, has asked the Food and Drug Administration to expand use of the drug to treat moderate to severe sleep apnea, in which people stop and start breathing during sleep, a spokesperson said Friday. A decision is expected by the end of the year.

But an outside expert cautioned in an editorial that more research will be needed to tell if the drug can be used as “a sole treatment” for obstructive sleep apnea, which occurs when tissue in the throat relaxes and collapses during sleep, fully or partially blocking the airway. It affects an estimated 20 million Americans and can cause short-term issues such as snoring, brain fog and daytime sleepiness but also severe long-term issues such as heart disease, dementia and early death.