Follow-up Studies of Primary Snoring(PS) and Obstructive Sleep Apnea Hypopnea Syndrome(OSAHS) in Chinese Children

In our study, there are 55 children of mild to moderate SDB with conservative treatment, among which 23 children are chosen in PS group and 32 children are chosen in OSAS group. For PSG, according to the value of OAHI to determine the improvement of the child, the value of OAHI is decreased by ≥ 25% for improvement. In the PS group, there were 2 cases with improvement, and the corresponding remission rate was 8.7%. In the OSAS group, there are 22 cases with improvement, and the corresponding remission rate was 68.8%. There was a significant difference between the remission rate of PS group and that of OSAS group (P<0.001).

There are five impact factors in the PSQ questionnaire, including: 1) nighttime snoring related symptoms (S); 2) sleep accompanying symptoms and related diseases (A); 3) daytime sleepiness related symptoms (L); 4) behavior related symptoms (B); and 5) others' evaluation of children's sleep (O).

In the PS group, there were significant difference for factor S, A and B at the time of 3 months and one year. For factor L, there was significant change at 3 months, while there was no significant change at half the year and one year.

In the OSAS group, there was significant change in the S factor for 3 months, half the year, and one year. While for the O factor, there was no significant change in any time. For factor A and L, there was a significant change in 3 months and one year. For the B factor, there was a significant difference at one year.

There was no significant difference in the level of leukotriene between PS and OSAS group. Also no significant difference in the level of leukotriene was detected among waiting, conservative or surgery group.

The controls were elder. Children in moderate-severe OSAS group were more boys and more obese. Because of the disease itself, there was statistic difference in AHI, OAI, ODI, respiratoryrelatedarousal index (ArI-resp), average SpO2 and lowest SpO2 among groups.The percentage of high level hs-CRP varied with the severity of SDB and cochran armitage trend test showed statistical significance (Z=-2.5109, p=0.012). In logistic regression analysis, OSAS, otitis media and BMI-z score were independent risk factors for high level hs-CRPafter adjusting for age and gender( p<0.0001). In multiple linear regression,after removing theconfounding factor of OSAS, it showed that high level hs-CRP was negatively correlated with SDNN, RMSSD, LF and HF respectively (p=0.003, p<0.001, p=0.007 and p=0.003 respectively).

There was no significant difference in the score of pictorial-based memory task among the control, PS and OSAS groups .Conclusion : Compared with the control group, both PS and OSAS group have abnormal sleep structure and respiratory parameters whereas no significant difference in the score of pictorial-based memory task .We couldn't demonstrate that sleep disordered breathing can affect children's ability of learning picture from the pictorial-based memory task in our study.

Both mild and moderateesevere OSA groups had lower RHI than PS (P < 0.001, P=0.001, respectively). Linear regression analysis revealed that RHI was positively correlated with age (r=0.17, P=0.002), BMI z score (r=0.14, P=0.008) and oxygen saturation nadir (r=0.15, P=0.006), but negatively correlated with oxygen desaturation index (ODI3%; r=0.19, P=0.001) and respiratory related arousal index (ArI-resp) (r=0.24, P < 0.001). In stepwise regression analysis, age, BMI z score, and ArI-resp were independently associated with endothelial function (r=0.34, P < 0.001).

Conclusion: Children with OSA are at increased risk for abnormal endothelial function than habitually snoring children. Furthermore, in addition to age and BMI, which are well-established factors affecting endothelial function, both intermittent hypoxia and sleep fragmentation during sleep also emerge as candidate risk factors contributing to endothelial dysfunction in snoring children