Sleep apnea increases cancer risk, study finds

People who suffer from sleep apnea—a disorder that causes abnormal breathing while sleeping, lowers oxygen levels and often is connected to snoring—are more likely to die of cancer, according to a new study from the University of Wisconsin.

Researchers found that the more severe a person’s sleep apnea, the greater the risk of dying from cancer. People with moderate sleep apnea were found to die at twice the rate of those without the disorder and those with severe sleep apnea die at a rate 4.8 times higher than those without it.

The World Health Organization estimates 100 million people worldwide have sleep apnea. Obesity is a leading risk factor for the disorder.

A research team led by Dr. F. Javier Nieto, chairman of the Department of Population Health Sciences at the University of Wisconsin School of Medicine and Public Health, examined 22 years of mortality data on 1,522 people from the long-running Wisconsin Sleep Cohort, a community-based epidemiology study of sleep apnea and other sleep problems. Participants undergo sleep studies and other tests at four-year intervals.

“This is really big news,” Dr. Joseph Golish, a professor of sleep medicine at the MetroHealth System in Cleveland who was not involved in the study, told The New York Times. “It’s the first time this has been shown, and it looks like a very solid association.”

While previous studies have associated sleep apnea with increased risks of hypertension, cardiovascular disease, depression and early death, this is the first human study to link sleep apnea with a higher rate of cancer mortality—a result that echoes previous findings in animal studies.

The research was presented at the American Thoracic Society’s 2012 International Conference in San Francisco in May.