Those who sleep less or more than the recommended seven to eight hours per night may be more prone to developing the chronic condition, which causes inflammation in the intestines, researchers report. The study authors concluded that duration and quality of sleep are key factors to be considered among patients with inflammatory bowel diseases.
"Both short and long durations of sleep have important health implications, and are associated with increased overall mortality, cardiovascular disease and cancer," study author Dr. Ashwin Ananthakrishnan, of Massachusetts General Hospital in Boston, said in an American Gastroenterological Association news release.
"Our findings indicate that ulcerative colitis may potentially be added to this list," he said. "We found that less than six hours of sleep per day and more than nine hours of sleep per day are each associated with an increased risk of ulcerative colitis."
The study, published recently in the journal Clinical Gastroenterology and Hepatology, included women enrolled in the Nurses' Health Study I in 1976 and the Nurses' Health Study II in 1989. Every other year, the women completed detailed questionnaires. The researchers noted the extended follow-up period allowed them to analyze the link between sleep and disease incidence.
In a previous study, the investigators also found that six months of poor sleep quality was associated with a twofold increase in risk of flare-ups for another inflammatory condition, Crohn's disease.
"All these data together support a growing recognition of the impact of sleep disruption on the immune system, and the need for providers to frequently inquire about sleep duration and quality as an important parameter of health in patients with inflammatory bowel diseases," Ananthakrishnan noted.
The study authors pointed out that their findings are limited by the fact that sleep duration was self-reported by the participants. The study also involved mostly white women, and was not representative of the general population.
Although the study found an association between ulcerative colitis and sleep duration, it did not prove a cause-and-effect relationship.
The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about ulcerative colitis.