Sleep-disordered breathing is associated with an increased risk of cancer mortality, according to a study.
Although previous studies have associated SDB with increased risks of hypertension, cardiovascular disease, depression and early death, this study is the first in humans to link the condition with a higher rate of cancer mortality, according to the researchers.
F. Javier Nieto, MD, PhD, MPH, the studys lead author and the chairman of the Department of Population Health Sciences at the University of Wisconsin School of Medicine and Public Health, said the study showed a nearly fivefold higher incidence of cancer deaths in patients with severe SDB compared with those without the disorder. The result echoes previous findings in animal studies.
“We are a long way from proving that sleep apnea causes cancer or contributes to its growth,” Nieto said in a news release. “But animal studies have shown that the intermittent hypoxia that characterizes sleep apnea promotes angiogenesis and tumor growth. Our results suggest that SDB is also associated with an increased risk of cancer mortality in humans.”
The researchers examined 22-year mortality data on 1,522 subjects from the Wisconsin Sleep Cohort, a longitudinal, community-based epidemiology study of sleep apnea and other sleep problems.
After adjustment for age, sex, body mass index and smoking, the researchers found that both all-cause and cancer mortality were associated with the presence and severity of SDB in a dose-response fashion. People with severe SDB died of cancer at a rate 4.8 times higher than people with no sleep breathing problems.
These associations were similar after excluding the 126 subjects who had used continuous positive airway pressure, and were stronger among non-obese subjects than obese subjects, the researchers said.
“In our large population-based sample, SDB was associated with an elevated risk of cancer mortality,” Nieto said. “Additional studies are needed to replicate these results. If the relationship between SDB and cancer mortality is validated in further studies, the diagnosis and treatment of SDB in patients with cancer might be indicated to prolong survival.”
The study was presented May 20 in San Francisco at the American Thoracic Societys 2012 international conference, and is scheduled for publication in the American Journal of Respiratory and Critical Care Medicine. To read the abstract and access the study via subscription or purchase, visit http://bit.ly/LlN7FE.