Late Breaking Abstract - The interplay of environmental tobacco smoke exposure and physical activity on sleep-disordered breathing in school-aged children

<bold>Background:</bold> While the adverse effects of environmental tobacco smoke (ETS) exposure and the benefits of physical activity (PA) on sleep health are well-documented, their interactive impacts on paediatric sleep-disordered breathing (SDB) remain to be elucidated. The current study aims to explore the potential buffering effects of PA against ETS-related SDB in Chinese school-aged children. <bold>Methods:</bold> This is a cross-sectional study conducted in the Yangtze River Delta Region of China. We collected data on children's demographics, ETS exposure status, PA levels and modes, as well as the presence of SDB via parent-reported questionnaires. We examined PA differences between children with and without ETS and investigated its associations with doctor-diagnosed sleep apnea and weekly snoring. <bold>Results:</bold> 275 children (age: 9.6±2.7 yrs.; boys: 56.7%) participated. Their overall prevalence of daily household ETS was 31.6%, most of the children (95.6%) had daily outdoor play while only 26.5% of them met the WHO recommendations of "60 minutes of moderate-to-vigorous physical activity (MVPA) per week". Sleep apnea and weekly snoring were reported in 6.9% and 32.0% of the children, respectively. Significant associations were found between ETS and SDB (p<0.001). Furthermore, daily outdoor activities significantly reduced the risk of sleep apnea (p=0.02) and weekly snoring (p=0.01), with higher PA levels correlating with lower risks. Notably, logistic regression revealed a significant interaction between ETS and PA on the prevalence of snoring (p=0.03). <bold>Conclusions:</bold> Regular PA may help alleviate some of the negative impacts of ETS on children's sleep and respiratory health.