Sleep apnea can raise risk of cancer, studies indicate

Two new studies indicate that people who suffer sleep apnea have a higher risk of developing cancer.

Due to be presented in San Francisco this week at an American Thoracic Society conference, the findings have been touted as "striking" by researchers, the New York Times reported.

Scientists say sleep apnea -- a widespread disorder suffered by 28 million Americans, which disrupts breathing and causes snoring -- is linked to low blood oxygen levels. That lack of oxygen can trigger the development of tumors.

One study, conducted at the University of Wisconsin School of Medicine and Public Health over 22 years, found that severe breathing problems at night increase the likelihood of dying from cancer by 4.8 times, compared to people who had no such breathing issues. People with moderate apnea were found to have double the risk of dying.

A second set of findings, from the Spanish Sleep Network, assessed the incidence of cancer, rather than the mortality rate.

Following 5,200 people over seven years, the study tracked oxygen depletion and found, for example, that people whose oxygen levels dipped below 90 percent, for up to 12 percent of the total time asleep, had a 68 percent greater likelihood of developing cancer, than people who did not have breathing difficulties at night.

Sleep apnea is widely understood to be related to obesity, diabetes, high blood pressure, heart attacks and strokes -- conditions that are also linked to cancer.

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