More than 936 million people have obstructive sleep apnea—the disorder’s first prevalence update in more than a decade—according to The Lancet Respiratory Medicine.

The Lancet published a multinational analysis by ResMed and 12 sleep researchers. The results were first presented at the American Thoracic Society 2018 International Conference in San Diego.

This figure is nearly 10 times greater than the World Health Organization’s 2007 estimate of more than 100 million, renewing calls for physicians to step up their efforts to screen, diagnose, and prescribe treatment for those who unknowingly have the disorder.

“More than 85% of sleep apnea patients are undiagnosed, meaning hundreds of millions repeatedly suffocate instead of getting healthy, restful sleep each night,” says Carlos M. Nunez, MD, a study coauthor and ResMed’s chief medical officer, in a release. “This raises their risk of workplace and roadway accidents, and can contribute to other significant health problems, such as hypertension, cardiovascular disease, or even poor glucose control for diabetic patients. We know the risks, and now we know the size of the problem is nearly 10 times greater than previously thought. Addressing it starts with screening patients we know to be high-risk.”

Why Is Sleep Apnea Mostly Undiagnosed?

“Many will attribute the resulting tiredness to aging or stress,” says Nunez. “Others will mention the problem to their doctor, only to be misdiagnosed with insomnia, migraines, chronic fatigue, or other conditions. Misdiagnosis is especially common with women, since sleep apnea was long thought to be much more common in men.”

Today, women account for 40% of newly diagnosed sleep apnea patients.

Another reason may be undiagnosed can be blamed on cultural ideas of what constitutes good sleep.

“For instance, some believe snoring may simply be a normal feature of how some people sleep, when in fact it’s one of the most important signs for the risk of having sleep apnea,” Nunez says. “With a global prevalence that approaches 1 billion people, patients and physicians need to consider the risks and ask the questions that may ultimately help them sleep and live better. This is no longer a problem that can be treated lightly or ignored.”

Who Is at Risk for Sleep Apnea?

More than half of all people with obesity, heart failure, stroke or transient ischemic attack (TIA), atrial fibrillation, or type 2 diabetes also have sleep apnea, according to research.

Snoring is the number-one indicator of sleep apnea in men and women, though not everyone who snores has it—and not everyone who has it snores.

People told they stop breathing for long periods during sleep are also at a higher risk for the disorder.

“The bottom line is: If you’re constantly tired or have other conditions linked to sleep apnea, it never hurts to ask your doctor about it,” Nunez says. “Don’t settle for being tired all the time. Sleep apnea is 100% treatable. You can improve your sleep, your mood, your relationships at work and home, your health, perhaps even other medical conditions you’re managing. But first, you have to find out.”