Dados do Trabalho

Título

The role of obesity in the sleep phenotype of sleep disorders in Youth with Prader–Willi syndrome based on polysomnographic analysis of respiratory events

Introdução

Prader–Willi syndrome (PWS) is a rare neuroendocrine disorder characterized by early hypotonia and feeding difficulties, developmental delays, endocrinopathies and behavioral concerns, especially rigidity, anxiety, and behavioral outbursts. PWS is also characterized by decreased resting energy expenditure and transition to hyperphagia and obesity. Sleep disorders are common findings in PWS, including excessive daytime sleepiness, narcolepsy-like symptoms, obstructive sleep apnea and hypoventilation. Although hypoventilation is a common finding in PWS, the role of obesity is still unclear.

Objetivo

To compare sleep ventilation profiles in obese and non-obese children and adolescents with PWS.

Métodos

Single night type 1 polysomnographic evaluation of children with PWS with regular clinical evaluation at a tertiary care facility. We performed a paired analysis comparing polysomnographic measures of obese and non-obese groups. Body mass index (BMI), BMI z-score, sleep efficiency and stages, apnea–hypopnea index (AHI), and oxygen saturation nadir values were longitudinally analyzed. Results are expressed as mean values and standard deviations (±SD). P values < 0.05 were considered statistically significant.

Resultados

We included 92 patients with available paired data. The median age was 9 years (range 0–24 years) and BMI was 33.2 ± 9.8 in the obese group and 19.7 ± 3.9 in the non-obese group. BMI z-score was 4.6 ± 3.3 in the obese group and 0.6 ± 1.0 in the non-obese group. There was a higher AHI (mean obesity = 10.9 ± 15.6 vs. mean non-obesity = 4.4 ± 3.6; t = 3.08, p = 0.002) and total sleep time spent with oxygen saturation (SO2) below 90% (mean obesity = 50.9 ± 95.9 vs. mean non-obesity = 8.6 ± 23.8; t = 3.27, p = 0.001) in obese group. The mean oxygen saturation (mean obesity = 92.2 ± 4.1 vs. mean non-obesity = 94.3 ± 1.7; t = 3.34, p = 0.001) was significantly lower in obese group. No differences were observed for lowest oxygen saturation (SO2 nadir), sleep stage, wake time after sleep onset and sleep efficiency.

Conclusões

Patients with PWS and obesity demonstrated significantly higher rates of respiratory events and worse oxygenation than those without obesity. The link between sleep and obesity in the PWS may due to energy imbalance from increased sedentary behavior. Further studies are needed to describe the phenotype of sleep in PWS.

Palavras -chave

Prader–Willi syndrome; obstructive sleep apnea; obesity; child; polysomnography.