How much sleep you get each night could affect your risk for ulcerative colitis, one of two inflammatory bowel diseases, a new study finds.
Sleep quality and duration are key predictors of overall health, and for good reason. Roughly 70 percent of the cells that make up the body’s immune system live on the walls of your gut. When one suffers, the other tends to follow. Diseases like ulcerative colitis and its partner in crime, Crohn’s disease, result when various parts of the digestive tract become inflamed — essentially an overreaction that something is wrong, when in reality everything’s fine.
Sleep may be one way of curbing that inflammation response. “Both short and long durations of sleep have important health implications and are associated with increased overall mortality, cardiovascular disease, and cancer,” said lead study author Dr. Ashwin N. Ananthakrishnan, of Massachusetts General Hospital, in a statement.
Interestingly, while sleep deprivation did coexist with a greater number of ulcerative colitis cases, after a certain length of time the risks began to rise again. The findings resulted in a U-shaped curve where too little sleep each night — defined as less than six hours — and too much — more than nine hours — upped people’s risks. These risks were independent of other environmental factors, such as age and weight, and other habits, including smoking and drinking.
To carry out their study, Ananthakrishnan and his colleagues analyzed data from women enrolled in the Nurses’ Health Study (NHS) I since 1976 and NHS II since 1989. Ninety percent of subjects followed up over the course of the study through detailed questionnaires twice a year. According to the researchers, the study’s long timeline and large sample sizes offer a unique look at the relationship between disease incidence and sleep duration.
There are some limitations. First, the study only included white female nurses, so it cannot make any claims about men or other races. In addition, respondents self-reported their sleep habits, which may paint an unrealistic picture of what’s really going on. However, the researchers say any self-reporting bias may be substantiated by the large size of each cohort.
Prior research may also uphold the findings. In 2013, Ananthakrishnan carried out a similar analysis in which he found Crohn’s disease patients experienced a twofold increase in their risk for flare-ups, even when they were in remission, when they reported poor sleep quality. “All these data together support a growing recognition of the impact of sleep disruption on the immune system,” he said.
In practical terms, he added, the findings should motivate health care providers like doctors and nurses to ask their patients about sleep quality and duration “as an important parameter of health in patients with inflammatory bowel diseases.”
With approximately 1.4 million Americans suffering from either ulcerative colitis or Crohn’s disease, and 70,000 new cases diagnosed each year, the upside could be huge. This is especially true given that scientists have yet to pin down a single cause for these diseases. There is also no cure.