Library

Notes: Background Epidemiological surveys have shown that the prevalence of asthma in the Asian population is relatively low. Within the Chinese population, schoolchildren from Hong Kong were found to have the highest rate of asthma.Objective To compare the prevalence of respiratory and atopic disorders, and to assess the role of atopy in the development of asthma, in Chinese schoolchildren from Hong Kong, Beijing and Guangzhou.Methods Community-based random samples of schoolchildren aged 9–11 years from three Chinese cities (Hong Kong, Beijing and Guangzhou) were recruited for study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. Subjects were studied by parental questionnaires (n = 10902), skin-prick tests (n = 3479) and skin examination (n = 3479).Results The prevalence rates of current wheeze, speech limiting wheeze, rhinoconjunctivitis and flexural dermatitis were significantly more common in Hong Kong than in Beijing or Guangzhou. The atopy rate was also higher in Hong Kong (41.2%) than in Beijing (23.9%) or Guangzhou (30.8%). Atopy was strongly correlated with current wheeze (OR 7.74; 95% CI = 5.70–10.51). Subgroup analyses of children from Hong Kong revealed that children born in mainland China who had subsequently migrated to Hong Kong had a significantly lower rate of allergic symptoms and atopy than those children born in Hong Kong.Conclusion Using a standardized written questionnaire along with a skin prick test and skin examination, we confirmed that the prevalence of asthma, allergic diseases and atopy was highest in schoolchildren from Hong Kong. Atopic sensitization is an important factor associated with asthma in Chinese children.

Notes: Background The International Study of Asthma and Allergies in Childhood (ISAAC) was designed to allow international comparison of epidemiological data on atopic conditions in childhood. In so doing, further aetiological information would be obtained that in turn would provide a framework for future studies. The global ISAAC results on the prevalence of atopic dermatitis indicated a 60-fold variation recorded in different countries. Such a degree of difference may be partially due to the translated questionnaires that were not validated in all of the involved countries.Objective To validate the Chinese version of the ISAAC core questions for atopic eczema.Methods One thousand nine hundred and twenty children aged between 3 and 5 were randomly recruited from 13 kindergartens in Hong Kong. Using a dermatologist's clinical examination as the gold standard, we validated the Chinese version of the ISAAC core questions for atopic eczema. The Youden's Indexes obtained in our study were compared with those obtained in the United Kingdom's validation study.Results The Youden's Indexes obtained in our study were significantly lower than those from the United Kingdom. The low scores were likely to be due to a reduction in the sensitivity of the Chinese questionnaire, which ranged from 23.5% to 70.6%.Conclusion Our findings indicate that the translated questionnaire is less effective than the English version in assessing the prevalence of atopic eczema. The indication of a low prevalence of atopic eczema among the Chinese population reported in previous studies was at least partially due to problems with the translated questionnaire.

Notes: Background A standardized protocol is essential for international comparisons of asthma prevalence and severity. The International Study of Asthma and Allergies in Childhood (ISAAC) used a standardized written questionnaire (WQ) and a video questionnaire (AVQ3.0) to survey the prevalence and severity of asthma in 13–14-year-old schoolchildren in different countries.Objective To compare the effectiveness of WQ and AVQ3.0 in predicting bronchial hyperresponsiveness (BHR), defined as having a provocation dose of inhaled methacholine causing a 20% fall in baseline FEV1 of 7.8μmol.Methods One hundred and eighty-nine Chinese schoolchildren completed a written questionnaire followed by a video questionnaire on asthma symptoms. They then underwent bronchial challenge to methacholine.Results Fair correlations were seen between the first two corresponding questions (moderate wheezing at rest and exercise wheeze) in the two questionnaires with Kapper indices of 0.44 and 0.43, respectively. The ability to predict BHR, as indicated by the Youden's index, was similar between the corresponding questions of the two questionnaires, except for ‘severe wheeze’ which had a significantly higher Youden's index in AVQ3.0 (0.44) than the corresponding question in WQ (0.11, P〈0.05).Conclusion The ISAAC International video questionnaire is at least as effective as the ISAAC written questionnaire in predicting BHR. It therefore provides a simple and valid tool for international comparisons of asthma prevalence and severity.

Notes: Background The prevalence of latex allergy in healthcare workers in Asian populations is unknown.Methods We studied 1472 employees in a teaching hospital in Hong Kong using written questionnaires and 133 respondents underwent skin prick testing to latex glove eluates and common allergens.Results Glove-related symptoms were common and 455 (30.9%) reported one or more symptoms, the majority of which could be classified as glove dermatitis (GD). On the other hand, symptoms suggestive of latex allergy such as urticaria, rhinitis, wheeze and asthma, were encountered less frequently and were noted by 3.3%. In particular, one developed asthma and two had wheezing, but there was no report of anaphylaxis. A total of 9.9% reported allergic symptoms from contact with other latex devices, in particular, rubber bands, rubber boots, goggles and swimming. Nine subjects (6.8%) had positive skin test to one or more of the five latex extracts. All were atopic to common allergens. Skin test positivity to latex and banana extracts was positively correlated (P 〈 0.05). In univariate logistic regression, daily glove use, personal history of allergic disease and history of allergic symptoms to latex-containing devices other than gloves were significant risk factors for both GD and LA. Nurses were more likely to complain of GD and workers with positive skin test to latex were 8.6 times more likely to have symptoms of LA. In multiple logistic regression, the remaining significant associations were between history of daily glove use and GD (OR = 50.11, 95% CI 15.88–158.13), and between positive latex skin test and LA (OR = 8.14, 95% CI 1.27–52.36).Conclusion Glove-related symptoms are common in healthcare workers in Hong Kong. Gloved healthcare workers are at risk of becoming sensitized to latex, and those with positive latex skin tests, long glove exposure time and frequent glove changes are at risk of clinical latex allergy.

Notes: Asthma is an inflammatory disease with a strong genetic predisposition. We have studied a group of unrelated asthmatic patients of southern Chinese origin on their HLA-DR and -DQ regions using molecular techniques and compared them with 104 healthy controls of the same ethnic origin. Restriction fragment length polymorphism (RFLP) was used to genotype the MHC class II DR β, DQ α and DQ β loci of the subjects. Polymerase chain reaction (PCR) using sequence specific primer (SSP) for DQ β genes was also performed. No significant difference was found in the HLA-DQ and -DR loci between the patients and the controls. All patients had their serum IgE antibody levels measured, bronchial reactivity assessed by histamine broncho-provocation and cutaneous reactivity to common allergens determined by skin-prick tests to Dermatophagoides pteronyssinus, Dermatophagoides farinae, mixed grass pollens, Aspergillus fumigatus, cat fur and dog dander and they were classified respectively. The HLA-DR and -DQ genotypes of these subgroups of patients were compared. There was no significant difference among these subgroups of patients according to their serum IgE levels, the degree of bronchial reactivity and whether they were positive for the skin tests for the various allergens respectively. The results suggest that HLA-DQ and -DR genotypes are not associated with asthma in southern Chinese people.

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 Asthma is a common health problem affecting patients of all ages. Because of the ease of sampling, epidemiological studies have concentrated mainly on the paediatric and general population.Objective This study aimed to determine the prevalence of wheeze, bronchial hyper-responsiveness and asthma amongst our elderly population and deduce any clinical and laboratory risk factors that might identify elderly asthmatics at an earlier stage.Methods Two thousand and thirty-two elderly Chinese aged ≥ 70 years, randomly selected from a registered list of all recipients of Old Age and Disability Allowances in Hong Kong, were administered a questionnaire on lung health. Two hundred and fifty subjects were invited to attend our laboratory for skin tests and pulmonary function tests and 179 agreed. Of these, 173 (96.6%) and 176 (98.3%) had eosinophil count and serum IgE levels measured, respectively. Two definitions of asthma were used: (1) bronchial hyper-responsiveness (BHR) plus current wheeze, and (2) history of wheezing without previous diagnostic labels of emphysema or chronic bronchitis.Results Fifteen patients (out of 179: 8.4%) reported wheezing over the past 1 year. Fifty-one patients (28.5%) demonstrated BHR on spirometry or histamine challenge tests. Seven patients had both symptoms of wheezing and evidence of BHR. The prevalence of asthma using this definition is therefore 3.9% (95% CI 1.6–7.9%). Nine patients had symptoms of wheezing without previous diagnostic labels of chronic bronchitis or emphysema and, using this definition, the prevalence is 5.0% (95% CI 2.3–9.3%). Using multiple logistic regression studies, sex, social class, age, smoking habits, serum IgE levels and eosinophil counts did not predict a diagnosis of asthma using either definition. We found no association between a positive skin test and any respiratory symptoms or illnesses including asthma.Conclusion Wheeze, bronchial hyper-responsiveness and asthma are prevalent amongst our elderly population. However, there were no identifiable demographic and laboratory risk factors in this study that may help us predict a diagnosis of asthma.

Notes: Background Royal jelly consumption has recently been linked with acute asthma, anaphylaxis and death. A cross-sectional survey was conducted to detennine the prevalence of and the relationship between royal jelly consumption and hypersensitivity reactions.Methods 1472 hospital employees of a teaching hospital in Hong Kong completed a questionnaire on royal jelly consumption and related allergic symptoms, and 176 questionnaire respondents and 300 consecutive asthma clinic patients were skin tested to royal jelly.Results Royal jelly consumption was high, with 461 out of 1472 subjects (31.3%) having taken royal jelly in the past. A total of nine subjects reported 14 adverse reactions to royal jelly, including urticaria, eczema, rhinitis and acute asthma. Thirteen out of 176 questionnaire respondents (7.4%) and 23 out of 300 consecutive asthma clinic attendees (7.3%) had positive skin test to pure royal jelly. All but one of the 36 subjects with positive royal jelly skin test were atopic to other common allergens. Positive associations were found between positive royal jelly skin test and atopy (OR = 33.73, 95% CI 4.51 to 252.11), adverse reactions to royal jelly and a history of clinical allergy (OR = 2.88, 95% CI 0.72 to 11.58), but not between royal jelly symptoms and previous royal jelly intake.Conclusion Royal jelly consumption is high in the community of Hong Kong. Atopic individuals are at high risk of sensitization to royal jelly but the precise relationship between royal jelly use, positive royal jelly skin test and clinical manifestations of adverse reactions to royal jelly, remains to be defined.