STUDY OBJECTIVES: It is unknown whether loudness of snoring or hypoxic burden are related to higher hyperactivity scores in habitually snoring children and whether this effect is impacted by the severity of sleep-disordered breathing (SDB). This study investigates the prevalence of hyperactivity in children with habitual snoring and the independent effects of loudness of snoring, as reported by the parents, hypoxic burden and obstructive sleep apnea syndrome's severity (OSAS) on hyperactivity, as measured by the Conners' Parent Rating Scale-Hyperactivity Index (CPRS-HI). METHODS: Children with habitual snoring aged 3-18 years were recruited for an overnight polysomnography reporting apnea-hypopnea index (AHI) and hypoxic burden, acoustic rhinometry, clinical examination and parental questionnaires assessing snoring loudness and CPRS-HI. RESULTS: The study analysis included 512 children (median (25th
75th percentile) age, 10.6 (7.6
13.4) years
295 (58 %) males), of whom 358 (70 %) were overweight or obese and 179 (35 %) had an obstructive AHI >
3/h. Findings revealed that 36 % [95 % CI: 32%-41 %] of children exhibited increased hyperactivity/impulsivity, and 25 % [21%-29 %] showed emotional lability. Snoring loudness was significantly correlated with higher hyperactivity scores, particularly for hyperactivity/impulsivity, while hypoxic burden showed no significant association (rho CONCLUSIONS: These results suggest that the loudness of snoring, independent of OSAS severity, contributes to hyperactivity in children.