Growth-related changes in the influence of obesity on signs suggesting sleep-disordered breathing and sleepiness in young individuals with Down syndrome.

ABSTRACT

BACKGROUND: Sleep-disordered breathing (SDB) is highly prevalent in individuals with Down syndrome (DS), who cease growing earlier than individuals without DS. These characteristics may be associated with increased obesity and subsequent SDB signs, such as snoring and apnoea or excessive daytime sleepiness (EDS). Thus, we assessed the influence of growth on the association between obesity and SDB signs or EDS; we used questionnaires sent to young individuals with DS and their caregivers, in a cross-sectional study. METHODS: We sent out 2000 questionnaires to individuals with DS and their caregivers. The surveys included questions about SDB signs (witnessed snoring or apnoea), subjective sleeping time including witnessed midnight arousal, the Epworth sleepiness scale and witnessed napping as well as sex, age, body weight and body height. RESULTS: Of the 1222 questionnaires we received, 660 were from young individuals and were included in the analysis. SDB signs were highly prevalent (77.1%), and frequency of SDB signs increased with growth (P-trend P = 0.02) in individuals with DS. Multivariate analyses showed that EDS (Epworth sleepiness scale > 10 points) was associated with body mass index Z-score (Z-BMI) in the 6-9 years age group (odds ratio [OR] 95% confidence interval [95% CI] 1.69 [1.09-2.62], P = 0.02). Conversely, SDB signs were associated with Z-BMI in the 13-15 (OR [95% CI] 1.99 [1.06-3.72], P = 0.03) and 16-18 years age groups (OR [95% CI] 3.04 [1.22-7.59], P = 0.02). For the 19-21 years age group, SDB signs were associated with only male sex (OR [95% CI] 7.28 [1.22-43.38], P = 0.03). CONCLUSIONS: This study showed that the association between Z-BMI and SDB or EDS was age dependent. In early school-age children with DS, high Z-BMI could not accurately predict the presence of SDB, but it was associated with EDS. In the pubescent period (i.e. 13-18 years), high Z-BMI was associated with SDB signs but not with EDS. Overall, obesity affected SDB signs and EDS differently based on age in young individuals with DS.