To assess whether primary snoring is associated with elevated blood pressure in non-overweight, prepubertal children, researchers from the Chinese University of Hong Kong compared ambulatory blood pressure (ABP) readings in children aged 6 to 13 years with and without snoring. Children for this study were selected from a larger obstructive sleep apnea (OSA) cross-sectional epidemiologic study. Only children Tanner stage 1 for breasts or genitalia and pubic hair with a BMI <85thpercentile were included. Exclusion criteria included history of upper airway surgery; intercurrent illness within four weeks; cardiac, renal, chromosomal, or neuromuscular abnormalities; and medications that could affect BP.
Parents completed a validated OSA sleep symptoms questionnaire that included assessment of snoring. Each child underwent a single nocturnal polysomnogram (PSG) and ABP monitoring on the same day as the PSG. Sleep and awake systolic BP (SBP), diastolic BP (DBP) and mean arterial BP (MAP) were monitored. Hypertension was defined as SBP or DBP >95th percentile of the ABP norm. A normal PSG was defined as an apnea-hypopnea index (AHI) <1, oxygen desaturation index (ODI) <1, and oxyhemoglobin saturation (SpO2) nadir ≥90%.
A total of 190 children (mean age 10.0 ± 1.5 years) were enrolled and separated into one of four groups: the control group of 56 children with a normal PSG reported to snore less than three nights per week; 46 participants with primary snoring (reported to snore ≥3 nights/week with normal PSG); 62 participants with snoring and an AHI of 1 to 3; and 26 participants with an AHI >3. There were no significant differences in demographic and anthropometric measures among the four study groups. The median number of BP readings during wakefulness and sleep was 12 and 9, respectively.
After adjusting for age, gender, and BMI, participants with primary snoring had significantly higher nighttime DBP compared with non-snoring subjects (mean difference = 3.2 mmHg; P=.016; 95% CI, 0.4–5.9). Significant increasing trends for daytime DBP, nighttime SBP, and nighttime DBP were seen. There was a statistically significant positive association between daytime and nighttime BP across the severity spectrum of sleep-disordered breathing, from no snoring, to primary snoring, to increasing AHI scores as a measure of worsening OSA. The authors conclude that their findings demonstrate primary snoring to be an aspect of the dose-response relationship between OSA and BP in children. Therefore, primary snoring should not be considered entirely benign.
Repetitive snoring affects approximately 10% of children and is a common presenting complaint of OSA. PSG is the gold standard used to distinguish between snoring due to OSA and primary snoring (essentially, snoring not associated with OSA). However, the distinction may not always be clear. Primary snoring is generally considered benign, but studies in adults have suggested that it is on one end of a...