Shorter sleep, snoring linked to poorer breast cancer survival

Women diagnosed with breast cancer who sleep less than the recommended seven hours per night and snored frequently are more to likely die from the disease, a new study has found.

The study reports that short sleep duration combined with frequent snoring reported prior to cancer diagnosis may influence subsequent breast cancer survival.

Breast cancer patients who reported sleeping 6 hours or less per night and snoring 5 or more nights per week before their diagnosis were 2 times more likely to die from breast cancer than patients who reported sleeping 7 to 8 hours per night and rarely snored.

"We were surprised to see that snoring, especially in combination with short sleep duration, had such a strong association with cancer survival for certain cancer types," said lead author Amanda Phipps, assistant professor at the University of Washington.

"To our knowledge, snoring has not previously been evaluated in relation to cancer survival, but our results suggest that it could be an important consideration," Phipps said.

The study group comprised 21,230 women diagnosed with a first primary invasive cancer during follow-up from the Women's Health Initiative (WHI), a longitudinal study of postmenopausal women.

Participants provided information on several sleep attributes at study baseline, including sleep duration and snoring.

Analyses were adjusted for potential confounders such as age at enrollment, cancer site, marital status, household income, smoking, physical activity and time lag between baseline data collection and cancer diagnosis.

The American Academy of Sleep Medicine recommends that adults should sleep 7 or more hours per night on a regular basis to promote optimal health.

According to the AASM, sleeping less than 7 hours nightly is associated with a variety of adverse health outcomes.

According to the researchers, epidemiologic studies of the relationship between sleep and cancer survival in humans have been limited.

However, mouse models have demonstrated that chronic sleep problems may contribute to accelerated tumour growth and shortened cancer survival.

One potential mechanism underlying this relationship is the adverse effect of poor sleep on inflammatory pathways, which may be a contributing factor in the development and progression of cancer.

"These findings reinforce our growing understanding that sleep has an effect on a broad range of health outcomes," said Phipps.

"Unlike so many things that can impact cancer risk and cancer prognosis, sleep is something that an individual can potentially control. Our results provide yet another reason to make quality sleep a priority," she said.

The study was published in the Journal of Clinical Sleep Medicine.