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 Feb. 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 six hours of sleep at night had an almost 50 percent increase in the risk of colorectal adenomas compared with individuals sleeping at least seven 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, 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 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 Pittsburg Sleep Quality Index (PSQI), which obtains information about the patient's overall sleep quality during the past month. The PSQI asks for such information as how frequently one has trouble sleeping and how much sleep one has had per night. The study was funded by the National Cancer Institute through Case Western Reserve University School of Medicine.
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 six hours compared to 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 (a measurement of obesity).
The researchers also found a slightly stronger association of sleep duration with adenomas with women compared to men, but the difference was not statistically significant.
Dr Li said the magnitude of the increase in risk due to less hours of sleep is comparable to the risk associated with having a first-degree relative (parent or sibling) with colon cancer, as well as with high, red meat intake. "Short sleep duration is a public health hazard leading not only to obesity, diabetes and coronary heart disease, but also, as we now have shown in this study, colon adenomas," he said. "Effective intervention to increase duration of sleep and improve quality of sleep could be an under-appreciated avenue for prevention of colorectal cancer."
Although why fewer hours of sleep may lead to colon cancer is unknown, Dr. Li said some of 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.
Dr. Li and other researchers on the study are also associated with the UH Seidman Cancer Center, the Case Comprehensive Cancer Center, the Department of Epidemiology and Biostatistics at Case Western Reserve University, the Center for Clinical Investigation at Case Western Reserve, and the Department of Medicine at UH and Case Western Reserve University School of Medicine.
About University Hospitals
University Hospitals serves the needs of patients through an integrated network of hospitals, outpatient centers and primary care physicians. At the core of our health system is University Hospitals Case Medical Center. The primary affiliate of Case Western Reserve University School of Medicine, University Hospitals Case Medical Center is home to some of the most prestigious clinical and research centers of excellence in the nation and the world, including cancer, pediatrics, women's health, orthopedics and spine, radiology and radiation oncology, neurosurgery and neuroscience, cardiology and cardiovascular surgery, organ transplantation and human genetics. Its main campus includes the internationally celebrated UH Rainbow Babies & Children's Hospital, ranked fourth in the nation for the care of critically ill newborns; UH MacDonald Women's Hospital, Ohio's only hospital for women; and UH Seidman Cancer Center, part of the NCI-designated Case Comprehensive Cancer Center. For more information, go to www.uhhospitals.org
About Case Western Reserve University School of Medicine
Founded in 1843, Case Western Reserve University School of Medicine is the largest medical research institution in Ohio and is among the nation's top medical schools for research funding from the National Institutes of Health. The School of Medicine is recognized throughout the international medical community for outstanding achievements in teaching. The School's innovative and pioneering Western Reserve2 curriculum interweaves four themes--research and scholarship, clinical mastery, leadership, and civic professionalism--to prepare students for the practice of evidence-based medicine in the rapidly changing health care environment of the 21st century. Eleven Nobel Laureates have been affiliated with the school.
Annually, the School of Medicine trains more than 800 M.D. and M.D./Ph.D. students and ranks in the top 20 among U.S. research-oriented medical schools as designated by U.S. News &World Report "Guide to Graduate Education."
The School of Medicine's primary affiliate is University Hospitals Case Medical Center and is additionally affiliated with MetroHealth Medical Center, the Louis Stokes Cleveland Department of Veterans Affairs Medical Center, and the Cleveland Clinic, with which it established the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University in 2002. http://casemed.case.edu.