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Notes: Background Many studies have reported an increase in the prevalence of asthma and related atopic disorders. The lack of standardized methodologies and ‘objective’ measurements make reliable comparison and monitoring of trends of asthma very difficult.Methods In this study, a total of 3321 schoolchildren aged 13–14 years were recruited for study using the Phase III Protocol of the International Study of Asthma and Allergic discase in Childhood (ISAAC). The results were compared with those obtained in the Phase I ISAAC study (1994–95), which used the identical and validated core questionnaires.Results The prevalence rates of physicians' diagnosis of asthma were similar in the two surveys (11.2% and 10.2%), but the prevalence rates of wheeze (written questionnaire) in the past year have decreased from 12.4% in 1994–95 to 8.7% in 2002 (P〈0.001). For the video questionnaire, all asthmatic symptoms in the preceding 12 months were significantly lower in 2002 when compared with those in 1994–95. Among the subjects with diagnosed asthma, the prevalence rates of wheeze in the past 12 months (written questionnaire) has decreased from 39.1% to 27.6% (P〈0.001). The prevalence rates of having wheezing attack at least once per month (video questionnaire) has decreased from 10.5% to 5.6% (P=0.013).Conclusion Using the same standardized and validated ISAAC questionnaire, the prevalence rates of asthma symptoms in Hong Kong Chinese schoolchildren have decreased since 1994. The exact reasons for such trend remain to be explored.

Notes: Background Exhaled nitric oxide (eNO) may represent a useful noninvasive marker of airway inflammation, but data on the reference population values in schoolchildren are limited. No reference eNO study in Asian children has been published.Methods Levels of eNO in a sample of 531 schoolchildren aged 11–18 years recruited from five schools (three international schools) in Hong Kong were measured online by a chemiluminescence analyser according to ERS/ATS standard. Each student also completed an International Study of Asthma and Allergic disease in Childhood questionnaire.Results Among the children without a physician's diagnosis of asthma or symptoms of wheeze, rhinitis and eczema, there were 258 Chinese and 33 Caucasians. In control Chinese children, the eNO level (median: interquantile range) was significantly higher (P〈0.001) in males (17.0 parts per billion (p.p.b.); 10.7–36.6) than in females (10.8 p.p.b.; 7.8–17.6). When compared with Caucasian control males (11.6 p.p.b.; 8.2–19.3) and females (9.1 p.p.b.; 7.5–11.9), the Chinese children had significantly higher eNO levels for both males (P=0.011) and females (P=0.037). For Chinese asthmatic males, the median eNO (interquartile range) was 39.8 p.p.b. (12.5–73.8), and for asthmatic females, 18.0 (9.6–56.3). After controlling for sex in Chinese controls, eNO did not have any significant correlation with height, weight and body mass index or body surface area.Conclusions This study demonstrates a gender difference of eNO level in healthy Chinese schoolchildren. When compared with Caucasians, Chinese children have significantly higher eNO levels.

Notes: Background Nitric oxide (NO) is a key factor for balancing T-helper type 1/T-helper type 2 immunity. Single nucleotide polymorphisms (SNPs) in nitric oxide synthase (NOS) genes have been associated with atopy and exhaled NO concentrations in Caucasians. We investigated the association between asthma traits and genetic polymorphisms in neuronal NO synthase (NOS1) and endothelial NO synthase (NOS3) in Chinese children.Methods Asthmatic children between 5 and 18 years of age and non-allergic controls were recruited. Plasma total IgE was measured by microparticle immunoassay, whereas allergen-specific IgEs were measured by fluorescent enzyme immunoassay. Fractional exhaled NO concentration (FeNO) was measured by a chemiluminescence analyser. NOS1 C5266T and NOS3 G894T were genotyped by restriction fragment length polymorphism, and (AAT)n polymorphism in intron 20 of NOS1 was determined by GeneScan analysis.Results The mean (SD) ages of 295 asthmatics and 174 controls were 11.1 (3.8) years and 11.6 (4.0) years, respectively (P=0.162). NOS1 C5266T and NOS3 G894T were not associated with asthma, atopy or FeNO. However, significantly more subjects with T/T in NOS1 C5266T had increased plasma total IgE as compared with those with C/T or C/C (P=0.017). This SNP was also associated with sensitization to Dermatophagoides pteronyssinus (P=0.049). Among asthmatic patients, log-transformed plasma total IgE levels were significantly higher among those homozygous for 5266T of NOS1 [mean (SD): 2.84 (0.44) for T/T, 2.68 (0.42) for C/T, 2.59 (0.69) for C/C; P=0.021]. This study found a significant inter-ethnic difference in the allele frequencies of AAT repeats, and this polymorphism was associated with high plasma total IgE levels (P=0.044) but not FeNO (P=0.158). NOS3 G894T was not associated with any asthma or atopy phenotype.Conclusions NOS1 C5266T and AAT repeats affect plasma IgE concentrations in Chinese children. On the other hand, neither NOS1 nor NOS3 SNP was associated with FeNO or the risk of having asthma.

Notes: Background Asthma is a common chronic disease and information on its management practices at the community level is helpful in identifying problems and improving asthma care.Objective To assess the severity status and management of the asthma symptom of wheeze of children at the community level in Hong Kong (HK) and Guangzhou (GZ).Methods Cross-sectional study of children aged 10 years using the International Study of Asthma and Allergic disease in Childhood (ISAAC Phase II protocol). Asthma management and lung function were assessed in 178 (98 from HK and 80 from GZ) randomly selected children with wheeze over the past 12 months.Results Eighty-three percent, 11%, 6% and 0% of children suffered from intermittent, mild persistent, moderate persistent and severe persistent asthma, respectively, according to the frequency of their symptoms. Addition of spirometric parameter only changed the asthma severity classification in 2.8% of children. Medications were used by 30.6% and 71.3% of children for wheeze in HK and GZ, respectively. In HK, inhaled β2-agonist (73.3% among the drug users) was the commonest medication used followed by inhaled corticosteroid (ICS) (23.3%). In GZ, inhaled β2-agonist was used by 75.4% of children, but use of ICS (26.3%), oral β2-agonist (26.3%), oral theophylline (45.6%), oral ketotifen (36.8%) and oral steroid (35.1%) were also common. ICS was only used by 11.4% of children with persistent asthma. Ten percent and 18.7% of children in HK and GZ, respectively, had emergency department visits, while 16.3% and 11.6% of children in HK and GZ, respectively, had missed school secondary to asthma over the past 1 year.Conclusions Most children in the community had intermittent asthma and addition of lung function to symptoms did not significantly affect classification of asthma severity. Significant morbidity was seen even in this group of children with mostly intermittent and mild persistent asthma.

Notes: Background Type 2 helper T lymphocyte-specific chemokines including macrophage-derived chemokine (MDC), thymus and activation-regulated chemokine (TARC) and eotaxin are important mediators for allergic airway inflammation.Objective We investigated whether these chemokines can be detected in exhaled breath condensate (EBC) and their relation to childhood asthma.Methods Asthmatics recruited from paediatric clinics of a university teaching hospital were classified into intermittent asthma (IA) and persistent asthma (PA) according to Global Initiative for Asthma guidelines. EBC was collected by a disposable collection kit, whereas fractional exhaled nitric oxide (FENO) was measured by a chemiluminescence analyser. Concentrations of MDC, TARC and eotaxin in both EBC and plasma were measured using sandwich enzyme immunoassay. The intra-subject reproducibility of exhaled chemokine measurements was determined by co-efficients of variation (CV).Results Forty-eight patients with PA, 36 children with IA and 18 controls were recruited. MDC and eotaxin were present in EBC from nearly all subjects, whereas TARC could be measured in EBC from 33 (32%) subjects only. The median MDC concentration in EBC was higher in PA (117 pg/mL) as compared with IA (106 pg/mL) and controls (105 pg/mL; P=0.003 for both). The median plasma MDC concentration in PA (648 pg/mL) was also higher than that in IA (520 pg/mL; P=0.002) and controls (490 pg/mL; P=0.008). The median plasma TARC concentration was also increased in PA as compared with IA (72 pg/mL vs. 35 pg/mL; P=0.004). MDC concentrations in EBC were lower in patients with PA who received high-dose inhaled corticosteroid (P=0.005). FENO was significantly higher in asthmatics than controls (P〈0.0001), but it was not associated with chemokines in EBC or plasma. The mean (range) CV for measuring MDC, TARC and eotaxin in EBC (n=6) were 5.5 (2.0−7.2%), 8.8 (3.6−14.4%) and 5.2 (2.8−7.9%), respectively.Conclusions Our results suggest that MDC in EBC and MDC and TARC in plasma are increased in children with PA as compared with IA or control. MDC concentrations in EBC are suppressed in patients on high-dose inhaled corticosteroid treatment.

Notes: Background Interleukin (IL)-13 is an important cytokine secreted from type 2 helper T lymphocytes. It is essential for modulating IgE synthesis by human B cells. Previous studies showed that polymorphisms in the IL-13 gene were associated with serum total IgE or allergic asthma. The relationship of this marker with sensitization to individual aeroallergens has not been evaluated.Objective We tested whether a polymorphism in the coding region of the IL-13 gene is associated with asthma and atopy in asthmatic children in Hong Kong.Methods We used restriction fragment length polymorphism to detect R130Q genotype in Chinese children with asthma and control subjects. Serum total IgE was measured by microparticle immunoassay and specific IgE to common aeroallergens was measured using fluorescent enzyme immunoassay. Pulmonary function studies were performed using spirometry.Results One hundred and fifty-seven patients and 54 control children were recruited. Their mean serum total IgE concentrations were 994 kIU/L and 473 kIU/L, respectively (P 〈 0.0001). Atopy as defined by ≥ 1 positive RAST was found in 141 patients and 32 control children. The GlnGln form of the R130Q polymorphism in the IL-13 gene was associated with serum total IgE (P = 0.005) as well as specific IgE to Der p 1 (P = 0.021), mixed cockroaches (P = 0.03) and dog (P = 0.003) but not with physician-diagnosed asthma (P = 0.621). In addition, the R130Q polymorphism did not correlate with subjective or objective indicators of asthma severity in our patients.Conclusion Our results suggest that the R130Q polymorphism of the IL-13 gene is associated with elevated serum total and allergen-specific IgE but not asthma in Chinese children.

Notes: There are at least 13 scoring systems for the assessment of disease severity in atopic dermatitis (AD). Each system has its problems with interobserver and intraobserver variability. Cutaneous T-cell attracting chemokine (CTACK) is a skin-specific chemoattractant which may correlate with AD severity and obviate the issue of observer reliability. We evaluated whether serum CTACK concentrations were associated with the severity of AD in children according to the SCORing Atopic Dermatitis (SCORAD) index. Thirty-seven Chinese children with AD (23 boys, 14 girls; aged 1–11 years) and 13 controls were recruited. The median (interquartile range) overall SCORAD for AD patients was 29.7 (20.3–49.7). Serum concentrations of CTACK and two other atopy-related chemokines, macrophage-derived chemokine (MDC) and thymus and activation-regulated chemokine (TARC), were measured by sandwich enzyme immunoassay. There were significant correlations between SCORAD (r = 0.394, P = 0.016), its area (r = 0.528, P = 0.001) and intensity components (r = 0.429, P = 0.008) with serum levels of CTACK. The serum concentrations of inflammatory markers MDC and TARC also correlated with the CTACK concentrations (r = 0.618, P 〈 0.001, and r = 0.587, P = 0.001, respectively). Serum CTACK concentration appears to be a skin-specific objective marker that correlates with various clinical and laboratory parameters of AD.

Notes: We evaluated the emollient use and bathing habits of children with atopic eczema (AE) managed at the paediatric dermatology clinic of a university teaching hospital, using children with noneczematous skin diseases as controls. Disease severity of AE in the preceding 12 months was evaluated by the Nottingham Eczema Severity Score. Three-quarters of patients with or without eczema preferred showering to bathing. Patients with AE were more likely to use bath oils than soap and to use emollients after a bath/shower. Review cases, however, were more likely to take a shower and for a longer time (10–30 min) than first-visit eczema patients. These habits did not vary with season or disease severity. Emulsifying ointment was the most commonly used agent for the bath/shower. Most patients applied emollient immediately after a bath/shower. However there were still significant proportions of AE patients who used soap (40% of first-visit vs. 27% of review cases) and who did not apply emollients after a bath/shower (25% of first-visit vs. 23% of review cases). It is important to determine whether this problem is due to inadequate patient education or whether other factors lead to poor compliance.

Notes: Summary Nonattendance in paediatric dermatology clinics is a significant problem. We reviewed the charts of all 400 new referrals to the Prince of Wales Hospital (PWH) paediatric dermatology clinic in the year 2000. Sixty-six patients (17%) did not attend. The mean age ± SD of attenders (7.5 ± 5.1 years) and nonattenders (7.7 ± 4.5 years) did not differ significantly. Forty-eight per cent of the referrals were females, 50% of the attenders were females and 67% of the nonattenders were male. Males were 2.1-fold more likely not to attend clinic relative to females (95% confidence interval 1.14–3.71, P = 0.010). Nonattendance was significantly higher among referrals from the PWH emergency department, compared with referrals by private practitioners (P = 0.05) and referrals by other clinics in the PWH. Data in this retrospective study confirm that there is a gender disparity in hospital nonattendance. More dermatological referrals but more nonattendance were associated with the male patients.

Notes: Leukotriene E4 (LTE4) is elevated in adults with atopic dermatitis (AD). We evaluated whether urinary LTE4 as a noninvasive marker correlates with clinical indices of disease activity in children with AD. AD patients aged 18 years or younger were eligible for inclusion in the study. Disease severity over the preceding 3 days was evaluated by the SCORing Atopic Dermatitis (SCORAD) index. Severity of AD over the past 12 months was evaluated by the Nottingham Eczema Severity Score (NESS) in Chinese. Urinary LTE4 concentration was measured by competitive enzyme immunoassay. One hundred and twenty-six children with AD (82 boys and 44 girls) and 45 controls were recruited. The mean ± SD urinary log-transformed LTE4 concentration in AD patients and controls was 2.94 ± 0.32 and 2.62 ± 0.20 pg/mg creatinine, respectively (P 〈 0.0001). SCORAD significantly correlated with NESS (r = 0.681, P 〈 0.0001). There were significant correlations between urinary LTE4 concentration and overall SCORAD score (r = 0.270, P = 0.002) and its extent (r = 0.185, P = 0.038) and intensity components (r = 0.247, P = 0.005), but not with NESS. When compared with mild AD, urinary LTE4 concentrations were higher in patients with moderate-to-severe disease (P = 0.049). Urinary LTE4 measurement is noninvasive and may be useful in supplementing the SCORAD for following longitudinal changes in AD severity in children. However, the practical value of this assay in a clinical setting remains to be determined.