Background: Unlike the adult sleep related disordered breathing (SDB) patients who are typically obese, the relation between obesity and childhood SDB is not clear. Aims: To investigate whether obese children are more at risk of obstructive SDB when compared to normal population, and whether this risk is potentiated by the presence of pharyngeal lymphoid tissue. Methods: Forty six obese children (age 10.8 (SD 2.3) years; BMI 27.4 (SD 5.1)), and 44 sex and age matched normal weight children (age 11.7 (SD 2.1) years; BMI 18 (SD 1.8)) were studied. All children underwent a set of physical examinations (including the upper airways) and sleep studies. Results: The obese children were different from the normal weight children in terms of type (predominantly obstructive), frequency, and severity of respiratory disturbances. Depending on the criteria used, 26% or 32.6% of obese children had SDB; 2.3% of normal controls had OAI >1 and 4.5% had RDI >5. Presence of SDB was related to presence of tonsils (size .2; range 0-4) (OR 12.67, 95% CI 2.14 to 75.17) and BMI (OR 1.20, 95% CI 1.08 to 1.33). Conclusions: Results suggest that obese children are at increased risk of obstructive SDB; the presence of any pharyngeal lymphoid tissue enlargement in obese children should therefore be aggressively managed.

The object of this study was to investigate the epidemiologic pattern of autism spectrum disorder in Chinese children. An autism spectrum disorder registry has been established in Hong Kong since 1986 by collecting data in a single center (the only university-affiliated child assessment center in Hong Kong). Since 1997, inpatient data from all public hospitals under the Hospital Authority have been stored in a central computerized program and retrieved from the Clinical Data Analysis and Reporting System. Clinical data have also been retrieved through the Clinical Data Analysis and Reporting System to ensure the completion of the registry, and these suspected cases have undergone the same diagnostic evaluation for autism spectrum disorder, as some of the new autism cases might be hospitalized in the public hospital. The incidence and prevalence of autism spectrum disorder have been calculated for the period of 1986 to 2005 using the population statistics available in the government for children less than 15 years old in Hong Kong. This study has included 4 247 206 person-years from 1986 to 2005 for children less than 15 years old and 1 174 322 person-years for those less than 5 years old in Hong Kong. Altogether, 645 children 0 to 4 years old with diagnoses of autism spectrum disorder were identified from 1986 to 2005. The estimated incidence of autism spectrum disorder was 5.49 per 10 000. The prevalence was 16.1 per 10 000 for children less than 15 years old for the same period. The male to female ratio was 6.58:1. This is the first reported epidemiologic study of autism spectrum disorder in Chinese children. The incidence rate is similar to those reported in Australia and North America and is lower than Europeans.

A predominant T helper cell type 2 cytokine and related immunological response was observed in infants with respiratory syncytial virus infection whereas a predominant pro-inflammatory cytokine response was observed in infants with influenza A infection. This may explain the different clinical manifestations of the two viral infections in infants.

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