Sleep disturbances and inflammatory bowel disease.

With an estimated 70 million Americans suffering, sleep disorders have become a global issue, and discovering their causes and consequences are the focus of many clinical research studies. Sleep is now also considered to be an important environmental and behavioral factor associated with the process of inflammation and the immune system. Increased sleepiness is considered part of the acute phase of response to tissue injury, and sleep loss activates inflammatory cytokines such as interleukin (IL)-1 and tumor necrosis factor (TNF)-α. Clinical studies in many immune-mediated diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and ankylosing spondylitis, have revealed an association of sleep disturbances with disease activity. Recent research suggests that individuals with sleep abnormalities are also at greater risk of serious adverse health, economic consequences, and most importantly increased all-cause mortality. The importance of sleep in inflammatory bowel disease has recently gained attention with some published studies demonstrating the association of sleep disturbances with disease activity, subclinical inflammation, and risk of disease relapse. A comprehensive review of sleep physiology and its association with the immune system is provided here. Experimental and clinical studies exploring this relationship in inflammatory bowel disease are reviewed, and the clinical implications of this relationship and future directions for research are also discussed.