Effect of weight loss on inflammation in patients with mild obstructive sleep apnea

Background and aims: Inflammation may be one mediating mechanism for cardiovascular diseases in obstructive sleep apnea (OSA). However, little is known about subclinical inflammation or the effect of lifestyle intervention on inflammation in early stages of OSA. The aim of this substudy of an existing randomized controlled trial, with post hoc analyses, was to determine the impact of lifestyle changes aimed at weight reduction on inflammatory biomarkers in overweight patients with mild OSA. Methods and results: Patients were randomized to supervised intensive lifestyle intervention group (N = 28) or to control group (N = 31), which received routine lifestyle advices. Circulating concentrations of pro- and anti-inflammatory mediators were measured before and after the 1-year intervention. The concentrations of two pro-inflammatory mediators, high-sensitivity C-reactive protein (hsCRP) and interleukin (IL)-6, decreased significantly in both groups. Although the changes in inflammatory biomarkers favored the supervised lifestyle intervention, the only significant reduction observed between the groups was for the anti-inflammatory IL-1 receptor antagonist (IL-1RA). The change in hsCRP was associated with apnea-hypopnea index, and improving night-time oxygen saturation was related to tumor necrosis factor alpha. IL-1RA and IL-6 were associated with insulin metabolism. Conclusion: Weight loss resulted in reductions in concentrations of some pro-and anti-inflammatory mediators in overweight patients with mild OSA, overall favoring the supervised lifestyle intervention. These findings suggest that more intensive treatment of obesity in OSA patients might be well-justified. Trial Registration clinicaltrials.gov ID: NCT00486746, June 7th 2007. (C) 2010 Elsevier B.V. All rights reserved.