Short Sleep Linked to Worsened Breast Cancer Survival
It’s another good reason to get snoring treated and make sure you’re getting enough sleep: it could improve your odds of surviving cancer. An analysis of a large pool of data shows that snoring and short sleep are correlated with lower cancer survival rates, especially breast cancer.
This insight comes after researchers analyzed data from the Women’s Health Initiative (WHI). Begun in 1991, the WHI includes a population of over 120,000 postmenopausal women. Researchers collected a large amount of data from these women when they joined the study, including how long they slept on average every night and whether they snored. Then women in the study were observed for over ten years.
Over the course of the study, more than 21,000 women developed cancer of some type. Researchers then analyzed the data from these women to determine the potential link between snoring, sleep, and cancer survival. They discovered that women who reported short sleep duration (≤ 6 hours) and frequent snoring (5 or more nights a week) had significantly poorer survival rates, being 1.32 times more likely to die following a cancer diagnosis.
Breast cancer survival rates were independently linked with short sleep (1.46 times less likely to survive) and snoring (1.34 times less likely to survive), and women who had both were about twice as likely to die of breast cancer than those who slept 7-8 hours and didn’t report snoring.
Sleep Apnea Could Make Cancer More Aggressive
The breast cancer study wasn’t designed to determine whether a causal link existed between the two conditions, but there are some intriguing potential ways that there could be a causal link between poor sleep and poor cancer survival. Perhaps the strongest potential link is inflammatory hormones.
Inflammatory hormones have been shown to increase a person’s cancer risk. Our body also can’t regulate inflammatory proteins as well when we get poor sleep. This includes both short sleep and sleep disrupted by snoring or sleep apnea. An excess of inflammatory proteins could contribute to cancer growth, making a person’s odds of success lower.
However, a better answer might come from a study looking specifically at mechanisms that link sleep apnea to cancer. Researchers at the University of Chicago and the University of Barcelona have shown that sleep apnea can change exosomes, and vital signals between cells, making cancer more aggressive.
Given this, it makes it critical that women in Detroit should consider a sleep test to see whether they have sleep-breathing disorders like sleep apnea.
Exosomes are a communication method that our cells use to carry vital information between them. An exosome is a vesicle–a packet of material enclosed in a lipid layer (similar to the cell membrane)–that emerges from the cell into the fluid of the body. It can be various molecules, but it can also be an actual cell organ.
We know that in addition to carrying information between healthy cells, exosomes can carry information between cancer cells and may be vital to the signaling process that turns a tumor malignant. They also help cancerous tumors grow their blood supply to support growth. And they can help protect cancer cells from attack by the immune system.
With all these key roles for exosomes, influencing exosomes would be a powerful method for controlling cancer–or worsening it.
Exosomes, Lung Tumors, and Sleep Apnea
Researchers wanted to see if lung tumors responded to sleep apnea. To test this, they took mice who had developed lung tumors. Half of the mice were kept in a normal atmosphere. The other half were exposed to intermittent hypoxia (oxygen shortage) to simulate the effects of sleep apnea.
The mice that were exposed to hypoxia saw more growth in their lung tumors. Their bodies also released more exosomes that contained RNA (genetic messenger molecules) that stimulated cancer.