Cardiovascular risks of children with primary snoring: A 5-year follow-up study

Background and objective: This study aimed to investigate if childhood primary snoring (PS) was associated with adverse cardiovascular outcomes at 5-year follow-up. Methods: This was a prospective matched cohort study. Subjects were recruited from a hospital-based cohort established from years 2006 to 2012 and they were aged 6-18 years at baseline. Each subject with PS was gender, age and BMI z-score matched with a control who had normal sleep study (obstructive apnoea-hypopnoea index [OAHI] < 1/h) and without habitual snoring (<3 nights/week) at baseline. All subjects underwent measurements of flow-mediated dilation (FMD) and carotid intima-media thickness (cIMT) and sleep study at baseline and follow-up visits. Twenty-four hour ambulatory blood pressure (ABP) was also recorded at follow-up. Results: Fifty-five case-control pairs were recruited and the length of follow-up was 5.1 +/- 1.3 years. At follow-up visit, subjects with PS at baseline had significantly lower FMD (-0.34% [-0.59 to -0.10]), greater cIMT (+0.01 mm [+0.001 to +0.013]), higher wake systolic blood pressure (SBP) (+2.6 mm Hg [+0.02 to +5.1]), sleep SBP (+3.0 mm Hg [+0.3 to +5.6]), sleep diastolic blood pressure (+2.2 mm Hg [+0.04 to +4.4]) and sleep mean arterial pressure (+2.2 mm Hg [+0.1 to +4.2]) compared to matched controls in the fully adjusted model for variables including change in OAHI and parental history of cardiovascular diseases. Conclusion: Childhood PS is associated with poorer endothelial function, greater cIMT and higher ABP at 5-year follow-up irrespective of change in obstructive sleep apnoea severity.