Urinary leukotriene E4, obesity, and adenotonsillar hypertrophy in Chinese children with sleep disordered breathing

Abstract

Study objectives: Sleep disordered breathing (SDB) has been associated with increased inflammatory responses. Changes in the level of pro-inflammatory leukotrienes (LTs) may initiate or exacerbate pediatric SDB and may play a major role in end-organ morbidity. The objective of the study was to investigate the relationship of LT productions with severity of SDB, obesity, and adenotonsillar hypertrophy in children.

Design/interventions: Prospective, observational study that included standard questionnaires, physical examinations, overnight polysomnography (PSG), and urinary leukotriene E(4) (LTE(4)) assay.

Setting: Sleep Center and Laboratory of Nutriology.

Patients or participants: 282 children with SDB and 94 healthy control subjects were recruited.

Measurements and results: Urinary LTE(4) levels were elevated in children with SDB compared to the controls, and LTE(4) productions emerged disease severity- and obesity-dependent increases. In stepwise multiple regression analysis, the independent predictors of the apnea-hypopnea index (AHI) included LTE(4) level and adenotonsillar-size sum score (P < 0.001 respectively; adjusted R(2)=0.318). A positive relationship between LTE(4) urinary level and adenotonsillar-size sum scores was present in the underweight/normal weight SDB subjects (r=0.276; P < 0.001), but not in the overweight/obese children (P > 0.05).

Conclusions: Systemic inflammation mediated by LTs participates in the pathophysiological mechanisms of SDB in children. The magnitude of inflammation as reflected by urinary LTE(4) is significantly related to the severity of SDB and obesity. However, a correlation between LTE(4) concentration and adenotonsillar size is present only among nonobese children.

Keywords: Sleep disordered breathing; adenotonsillar hypertrophy; leukotriene E4; obesity; polysomnography; systemic inflammation.

Figures

Figure 1

(A) LTE4 levels in morning urine obtained from children with severe/moderate/mild SDB and control subjects (P < 0.001). (B) LTE4 levels in morning urine obtained from 282 children with SDB stratified by obesity (P < 0.001). Boxes represent values within the interquartile rage; whiskers represent the data range; and the line across the boxes, median values.

Figure 2

(A) Scatterplot between log-transformed LTE4 concentration and adenotonsillar-size sum score in 194 nonobese children (r = 0.276; P < 0.001). (B) Scatterplot between log-transformed LTE4 concentration and adenotonsillar-size sum score in 88 overweight/obese children (difference not significant).