Excerpts from a lengthy article on the relationship between sleeplessness and cancer, authored by Lisa Collier Cool, are below. The full article can be seen here: http://health.yahoo.net/experts/dayinhealth/troubled-sleepers-face-increased-risk-cancer
Researchers have found surprising links between lack of sleep and several types of cancer, including prostate, breast, and colon cancer, among others.
Men who reported trouble sleeping were up to twice as likely to develop prostate cancer as those who slept well, according to a new paper published in the journal, Cancer, Epidemiology, Biomarkers & Prevention. This association was even stronger in cases of advanced prostate cancer, and the risk increased relative to the severity of the sleep problems. (This study was done in Iceland.)
Too little sleep may also contribute to the recurrence of breast cancer among women, according to a recent study published in Breast Cancer Research and Treatment.
The researchers surveyed 412 women diagnosed with pre-menopausal breast cancer about their average length of sleep each night. Their analysis of participants’ responses and medical records uncovered a link between duration of slumber and cancer recurrence, as well as aggressive tumors. Women who slept an average of six hours or less each night were more susceptible to cancer recurrence than women who caught more z’s.
Another recent study from Case Western Reserve University School of Medicine found that people who snooze for less than six hours each night are at 50% greater risk of developing colorectal adenomas than those who sleep for seven hours or more . . . Even after adjusting for other risk factors, including family history, waist-to-hip ratio (a measure of obesity), and smoking, there was a clear link between sleep deprivation and adenomas.
Li Li, M.D., a family physician and Associate Professor of Family Medicine, Epidemiology and Biostatistics at Case Western Reserve University School of Medicine, theorized that, “less sleep may mean less production of melatonin, a natural hormone that in animals has been linked to DNA repair.” In animal studies samong mice and rats, melatonin has been shown to prevent and delay cancer growth.
Li also suggests that, “insulin resistance may underlie the link between sleep disturbance and cancer development.” This hypothesis is supported by previous research findings, which have identified potential links between chronic sleep loss, insulin resistance, obesity, and cancer.