New York, NY – May 6, 2020 – A new study of nearly 34,000 individuals who underwent sleep studies at four large Ontario academic hospitals has found a link between obstructive sleep apnea (OSA) and the development of cancer. The study was posted online in the Abstract Issue of the American Journal of Respiratory and Critical Care Medicine (Abstract #6414. Title: Obstructive Sleep Apnea and Incident Cancer: A Large Historical Multicenter Clinical Cohort Study).
“Chronic hypoxemia (low blood oxygen) and fragmented sleep are mechanisms by which obstructive sleep apnea is proposed to contribute to cancer development,” said the study’s first author, Tetyana Kendzerska, MD, PhD, associate scientist at The Ottawa Hospital and assistant professor, Division of Respirology, University of Ottawa. “However, epidemiological evidence linking OSA and cancer is still inconclusive.”
Dr. Kendzerska and colleagues sought to gather this evidence. They looked at linked individual clinical and polysomnographic data – a range of data on patients gathered through technologies used in overnight sleep studies – from sleep clinics and provincial health administrative databases, as well as information on cancer status and type from the Ontario Cancer Registry. In individuals free of cancer at the study’s start (the date of the sleep study), statistical analyses were applied to examine the severity of OSA at the start of the study period and the cancer development in follow-up. They controlled for known cancer risk factors such as age, sex, alcohol use disorder, smoking, obesity, as well as comorbidities at baseline.
The researchers found that severe OSA, defined as number of episodes of more than 30 per hour in which breathing stopped during sleep, was significantly associated with a 15 percent increased risk of developing cancer, compared with individuals with no OSA. Severe nocturnal hypoxemia was associated with a 30 percent greater cancer risk.
“We looked at specific cancer subtypes as well,” said Dr. Kendzerska. “Limited by a relatively small sample size and multiple comparisons, we found colorectal, kidney, lung and smoking-related cancer subtypes to be all directionally consistently associated with increased hazard of incident cancer, adjusting for known risk factors.”
She added, “Our study has limitations, such as the fact that it was observational and historical, and was conducted only at academic medical centers. Keeping these limitations in mind, I believe our results are conclusive given that they are based on about 30,000 adults free of cancer at baseline, more than 2,000 of whom developed cancer.”
