Phoenix Sleep Doctors: Does Sleep Apnea Cause Cancer?

Jun 28, 2012 | Sleep and health

Do you know the link between sleep apnea and cancer? (Image via ~Twon~ on Flickr)

Thanks to research conducted in recent years, the dangers of sleep apnea are well known.   People with untreated sleep apnea experience higher rates of diabetes, obesity, and cardiovascular disease.  But new research shows that the diagnosis of sleep apnea may carry with it another grave risk as well, a higher risk of cancer.  For the 28 million Americans with sleep apnea, this should serve as a long overdue wake-up call to get diagnosed and pursue treatment.

In the first of two studies, researchers in Spain found that those with the most severe types of sleep apnea had a 65% greater chance of developing some form of cancer.  This study was conducted by the Spanish Sleep Network and involved following more than 5,000 people over a period of 7 years. At the start of the study, participants had no cancer diagnosis but did have sleep apnea.  The research team looked at two factors for each participant, their hypoxemia index and the incidence of cancer.  The hypoxemia index gauges how much time a person spends with a blood oxygen level under 90% during the night.  This is a solid indicator of the severity of the apnea.

The results of this study show that the more severe the apnea, the more likely it was that the participant would be diagnosed with some form of cancer during the study.   If a participant spent 12% of their time asleep with an oxygen level under 90%, their cancer risk is 68% higher than that of a person who doesn’t experience decreased blood oxygen during sleep.

The other study was conducted by a team at the University of Wisconsin School of Medicine and Public Health.  Using data from the Wisconsin Sleep Cohort study, which has been monitoring the sleep and health of participating state employees since 1989, also found the sleep apnea – cancer link.  This study focused more on mortality than incidence however and the findings further underline the gravity of this condition.  While those with the most severe sleep apnea are 65% more likely to be diagnosed with cancer, these same people are also almost 5 times as likely to die from cancer as people without sleep apnea.  Although the picture is rosier for people with moderate sleep apnea, it isn’t much better as this group was shown to be twice as likely to die from cancer as someone without the condition.

In both studies, the research teams found no change in the results after ruling out other risk factors for cancer like age, alcohol use, weight, activity level, and smoking.  This means that even after accounting for those well-known cancer risk factors, those with sleep apnea were still more likely to be diagnosed with cancer and more likely to die from cancer than those without the condition.

Both studies are being presented at the American Thoracic Society’s international conference and open the door to future research into the reason for this correlation and the affect of current and future treatment protocols on these findings.

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