Researchers were not able to find a significant link between sleep apnea and cancer.
Obstructive sleep apnea occurs when people stop breathing for short periods during the night, the Canadian Medical Association Journal reported. The condition has been linked to a number of health risks, but cancer may not be one of them.
In the past researchers have suggested obstructive sleep apnea may be linked to cancer because the condition causes lower levels of oxygen in the bloodstream.
"There is a need for a sufficiently large cohort study with a long enough follow-up to allow for the potential development of cancer that adjusts for important potential confounders, examines common cancer subtypes and has a rigorous assessment of both obstructive sleep apnea and cancer," wrote Doctor Tetyana Kendzerska, Institute for Clinical Evaluative Sciences (ICES) and Women's College Hospital, University of Toronto, Toronto, Ont., with coauthors.
To make their findings the researchers looked at 10,149 patients with obstructive sleep apnea who participated in a study taking place between the years of 1994 and 2010. At the start of the study 5.1 percent of the participants had a cancer diagnosis. In the follow-up period 6.5 percent of people who did not have cancer at the beginning of the study had a baseline incident. Prostate, breast, colorectal and lung cancers were found to be the most common in the study.
"We were not able to confirm previous hypotheses that obstructive sleep apnea is a cause of overall cancer development through intermittent hypoxemia [low blood oxygen levels]," wrote the authors. "However, in subgroup analyses, we found that the level of oxygen desaturation was associated with the development of smoking-related cancer."
The study was conducted by researchers at ICES; Women's College Hospital; St. Michael's Hospital; University Health Network; Mount Sinai Hospital; Sunnybrook Health Sciences Centre; and the Institute of Health Policy Research, University of Toronto, Toronto, Ont.
