An inadequate amount of sleep has been associated with higher risks of obesity, heart disease, diabetes, and death. Now colon cancer can be added to the list.
In a ground-breaking new study published in the February 15, 2011, issue of the journal Cancer, researchers from University Hospitals (UH) Case Medical Center and Case Western Reserve University School of Medicine, found that individuals who averaged less than 6 hours of sleep at night had an almost 50% increase in the risk of colorectal adenomas compared with individuals sleeping at least 7 hours per night. Adenomas are a precursor to cancer tumors and, left untreated, they can turn malignant.
"To our knowledge, this is the first study to report a significant association of sleep duration and colorectal adenomas," said Li Li, MD, PhD, the study’s principal investigator and family medicine physician in the Department of Family Medicine at UH Case Medical Center and associate professor of Family Medicine, Epidemiology and Biostatistics at Case Western Reserve University School of Medicine. "A short amount of sleep can now be viewed as a new risk factor for the development of colon cancer."
In the study, patients were surveyed by phone prior to coming into the hospital for scheduled colonoscopies at UH Case Medical Center. They were asked demographic information as well as questions from the Pittsburgh Sleep Quality Index (PSQI).
Of the 1,240 patients, 338 were diagnosed with colorectal adenomas at their colonoscopy. The patients with adenomas were found in general to have reported sleeping less than 6 hours compared to those patients without adenomas (control) patients, and the association between amount of sleep and adenomas remained even when adjusted for family history, smoking, and waist-to-hip ratio.
Although why fewer hours of sleep may lead to colon cancer is unknown, Li said theories include that less sleep may mean less production of melatonin, a natural hormone that in animals has been linked to DNA repair, or that insulin resistance may underlie the link between sleep disturbance and cancer development.