Sleep-disordered breathing and cardiometabolic and inflammatory markers in children with overweight/obesity: The role of cardiorespiratory fitness.

Objectives: To investigate the association of sleep-disordered breathing (SDB) severity with cardiometabolic and inflammatory markers independently of the adiposity levels; and to explore the role of cardiorespiratory fitness in these associations in children with overweight/obesity.

Methods: A total of 109 children aged 8-11 years with overweight/obesity were included in this cross-sectional study. SDB was assessed using a scale of the reduce version of the Paediatric Sleep Questionnaire. Cardiometabolic markers included fasting blood lipids biomarkers (i.e., low- and high-density lipoprotein cholesterol, and triglycerides), blood pressure, insulin, glucose, and the homeostatic model assessment index. Inflammatory markers (i.e., interleukin-6, interleukin-1β, C-reactive protein [CRP], and tumour necrosis factor alpha) were analysed. Cardiorespiratory fitness was assessed by the 20 m shuttle-run test.

Results: No significant associations were found between SDB severity and most of the cardiometabolic markers after correcting for adiposity and multiple comparisons (all p's >0.05). SDB severity was positively related to CRP (β = 0.352, p = 0.002), yet not with the remaining inflammatory markers analysed. The interaction effect of cardiorespiratory fitness presented a positive trend in the association of SDB with CRP (p = 0.1). When stratified analyses by cardiorespiratory fitness levels were conducted, a positive relation was found between SDB and CRP in the low cardiorespiratory fitness group (β = 0.465, p = 0.014), but not in the high cardiorespiratory fitness group (β = 0.236, p = 0.108).

Conclusion: SDB severity was positively associated with CRP independently of the adiposity levels, but not with other inflammatory or cardiometabolic risk factors in children with overweight/obesity. Moreover, our results suggest that higher levels of cardiorespiratory fitness may attenuate the adverse effect of SDB severity on systematic inflammation in children with overweight/obesity.