Inflammatory processes occur throughout the body, with a primary function of promoting healing after injury. However, when too active, these inflammatory processes can also damage the body in many ways, and may contribute to heart disease, stroke, certain cancers, and other significant medical problems. Stress, including sleep disturbance, is a major contributor to inflammation in the body. Insomnia, one of the most common sleep disorders, is associated with increased risk for depression, medical comorbidities, and mortality.
A new study reports that treatment for insomnia, either by cognitive behavioral therapy or the movement meditation tai chi, reduces inflammation levels in older adults over 55 years of age.
“Behavioral interventions that target sleep reduce inflammation and represent a third pillar, along with diet and physical activity, to promote health and possibly reduce the risk of age-related morbidities including depression,” said Dr Michael Irwin, who conducted this work along with his colleagues at the Cousins Centre for Psychoneuroimmunology at the University of California Los Angeles.
For this study, the researchers recruited 123 older adults with insomnia who were randomised to receive one of 3 types of classes: cognitive behavioural therapy for insomnia, the movement meditation tai chi, or a sleep seminar (the control condition).
They found that treatment of sleep disturbance with cognitive behavioural therapy for insomnia reduces insomnia symptoms, reduces levels of a systemic marker of inflammation called C-reactive protein, and reverses activation of molecular inflammatory signalling pathways. These benefits were maintained throughout the study’s16-month follow-up period.
Tai chi, a lifestyle intervention that targets stress that can lead to insomnia, was also found to reduce inflammation, and did so by reducing the expression of inflammation at the cellular level and by reversing activation of inflammatory signalling pathways. The reduction of cellular inflammation was also maintained during the 16-month follow-up. Those participants assigned to the sleep seminar classes showed no significant changes in inflammatory markers, as expected.
These results provide an evidence-based molecular framework to understand how behavioural interventions that target sleep may reduce inflammation and promote
“This study suggests that there are behavioural approaches that can improve sleep, reduce stress, and thereby improve health,” commented Dr John Krystal, editor of Biological Psychiatry. “It is a reminder, once again, that there is no health without mental health.”
Sleep disturbance is associated with activation of systemic and cellular inflammation, as well as proinflammatory transcriptional profiles in circulating leukocytes. Whether treatments that target insomnia-related complaints might reverse these markers of inflammation in older adults with insomnia is not known.
In this randomized trial, 123 older adults with insomnia were randomly assigned to cognitive-behavioral therapy for insomnia (CBT-I), tai chi chih (TCC), or sleep seminar education active control condition for 2-hour sessions weekly over 4 months with follow-up at 7 and 16 months. We measured C-reactive protein (CRP) at baseline and months 4 and 16; toll-like receptor-4 activated monocyte production of proinflammatory cytokines at baseline and months 2, 4, 7, and 16; and genome-wide transcriptional profiling at baseline and month 4.
As compared with sleep seminar education active control condition, CBT-I reduced levels of CRP (months 4 and 16, ps < .05), monocyte production of proinflammatory cytokines (month 2 only, p < .05), and proinflammatory gene expression (month 4, p < .01). TCC marginally reduced CRP (month 4, p = .06) and significantly reduced monocyte production of proinflammatory cytokines (months 2, 4, 7, and 16; all ps < .05) and proinflammatory gene expression (month 4, p < .001). In CBT-I and TCC, TELiS promoter-based bioinformatics analyses indicated reduced activity of nuclear factor-κB and AP-1.
Among older adults with insomnia, CBT-I reduced systemic inflammation, TCC reduced cellular inflammatory responses, and both treatments reduced expression of genes encoding proinflammatory mediators. The findings provide an evidence-based molecular framework to understand the potential salutary effects of insomnia treatment on inflammation, with implications for inflammatory disease risk.