Sleep Disturbance Linked to Inflammatory Diseases

Too much or too little sleep is associated with an increase in inflammation, a new meta-analysis published in Biological Psychiatry found.

The US Centers for Disease Control and Prevention considers lack of sleep a public health epidemic and sleep disturbances, such as insomnia, have been associated with an increased risk of inflammatory disease and mortality.

As a response to inflammation, C-reactive protein (CRP) and interleukin-6 (IL-6) proliferate and circulate in the blood stream, which predicts adverse health issues including, hypertension, type 2 diabetes, and cardiovascular events. Although there have been numerous studies investigating the mechanism behind the association between immunity and sleep health, variations among the studies made it difficult to understand the effects.

For the current study, researchers systematically reviewed 72 articles that included more than 50,000 participants from population-based and clinical studies to find associations between sleep and inflammatory markers. Researchers examined tumor necrosis factor α (TNFα), CRP, and IL-6 as indicators of inflammation.

The results of the meta-analysis showed that sleep disturbance defined as poor sleep quality or complaints of insomnia and long sleep duration, defined at more than 8 hours, were associated with increased levels of CRP. There were no associations found with TNFα.

“It is important to highlight that both too much and too little sleep appears to be associated with inflammation, a process that contributes to depression as well as many medical illnesses,” said editor of Biological Psychiatry, John Krystal.

The authors noted that insomnia or sleep disturbances should be considered behavioral risk factors for inflammation, similar to adverse effects of a high fat diet or sedentary lifestyle. A strategy for reversing inflammation and reducing the risk of inflammatory illnesses could be treatments that target sleeping behavior.

“Together with diet and physical activity, sleep health represents a third component in the promotion of health span,” said researcher Michael Irwin.