A study by researchers at the University of California, Los Angeles (UCLA) in 2014, demonstrated that treating insomnia could lead to decreases in inflammation and that cognitive behavioural therapy proved better than other forms of treatment for insomnia. Sleep appears to be both a partial cause of and consequence of inflammation.

Appearing in the journal Sleep, the study showed that in 123 adults older than 55, treating insomnia led to decreases in C-reactive protein (CRP), a marker of inflammation. Found in blood plasma, CRP levels were measured at the beginning of the study, following treatment, and again in a follow-up study 16 months later.

"What we found particularly intriguing was that the levels of the CRP inflammatory marker remained low even 16 months after treating the insomnia," Michael Irwin, the lead author, and professor of psychiatry at the UCLA Semel Institute for Neuroscience and Human Behaviour, said.

In untreated insomnia, the CRP levels simply continued to rise. "Together, these findings indicate that it is even more critical to treat insomnia in this population who are already at elevated risk for ageing-related inflammatory disease,” said Irwin.

Historically, researchers have found similar results

A meta-analysis conducted in 2016, by Irwin further expounded his theory. Analysis of 72 different papers, which totalled over 50,000 participants from population-based and clinical studies, found that even factors like sleep disturbances and sleep duration increase inflammation.

Published in Biological Psychiatry, the report highlighted that sleeping for longer than eight hours was associated with increased levels of CRP and Interleukin-6. These are predictors of cardiovascular diseases, hypertension, and type 2 diabetes. It seems that disturbed sleep could be as bad as a poor diet and sedentary lifestyle.

Drug companies have yet to play catch-up

Despite these results, drug companies, which in the past have been eager in to capitalise on sleep problems, have yet to develop treatments on the connection between sleep and inflammation.

Understanding these pathways “allows us as scientists now to target sleep or inflammation to alter health outcomes in ways that we didn’t know would be effective five years ago,” Irwin said. The few steps that drug companies have taken have mostly been in anti-inflammatory drugs.

Genentech for example sponsored a study last year that examined how well patients with chronic hives slept whilst taking their anti-inflammatory drug Omalizumab. Through three trials, patients who took the drug, reported fewer sleeping problems than those who did not.

Other drug companies are interested in measuring sleep habits through apps. Johnson and Johnson’s Gut Check app for example, enables patients of inflammatory bowel disease to record how much sleep they have received each night.

Drug manufacturers’ biggest problem however is how difficult it is to objectively measure sleep. Equally challenging, is that not all patients respond to traditional treatments for insomnia. As Irwin notes, only half of patients responded to cognitive behavioural therapy in his study.

“Why didn’t the other 50% respond? Well, maybe they have an underlying inflammation that needs to be targeted along with their sleep,” he said. MIMS

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