Asthma, allergy and atopy in southern Chinese school students

Time-trends for eczema prevalences among children and adults from 1985 to 2015 in China: a systematic review

Background

Several studies have reported that childhood prevalence of eczema has been increasing worldwide. However, none study quantitatively evaluated prevalence trends of eczema among children and adults in the last 30 years in China.

Methods and Findings

Via a systematic review of literature databases in English and Chinese, we summarized all studies reporting eczema prevalences from 1985 to 2015 in China as well as diagramed prevalence and eczematous population trends against year for different age groups. A total of 93 studies and 17 studies (16 for children and one for adults) were selected for qualitative and quantitative synthesis, respectively. Childhood lifetime-ever eczema prevalences ranged from 10.0% to 30.0%. Prevalences among 3-12-year-olds children showed increasing trends in most specific cities, but national lifetime-ever eczema prevalences among 13-14-year-olds children decreased from 10.6% in 2001 to 8.6% in 2009 in mainland China. We estimated that about 1.5 million children aged 13-14-year-olds in 2009 and 15.5 million children aged 3-6-year-olds in 2012 had lifetime-ever eczema in mainland China. Similar studies were too few to ascertain time-trends of eczema prevalence among adults. About 39.4, 20.0, and 11.6 million adults aged 15-86-year-olds in 2010 had contact dermatitis, seborrheic dermatitis, and atopic dermatitis in the mainland China, respectively.

Conclusions

The burden of eczema became heavier in young children, whereas perhaps had been reduced in adolescent in China. More studies for eczema prevalence in adults are warranted.

How does parental history of atopic disease predict the risk of atopic dermatitis in a child? A systematic review and meta-analysis

BACKGROUND

Parental history of atopic disease is a well-established risk factor for the development of atopic dermatitis (AD), but several aspects of this association remain unclear.

OBJECTIVE

We sought to determine the association of parental history of atopic disease with AD in offspring.

METHODS

We searched PubMed and EMBASE through June 2018 for relevant records and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled odds ratios (ORs) with 95% CI were calculated using random-effects models.

RESULTS

A total of 163 records covering 149 unique studies were included. Of these, 119 studies were included in the meta-analysis. Individuals with parental history of atopic disease had increased odds of AD (OR, 1.81; 95% CI, 1.65-1.99). Parental asthma (OR, 1.56; 95% CI, 1.18-2.05) and allergic rhinitis (OR, 1.68; 95% CI, 1.34-2.11) had a smaller effect than AD (OR, 3.30; 95% CI, 2.46-4.42). The effect of maternal and paternal history was comparable for all atopic diseases. An increase in odds was observed when comparing the effect of having 1 (OR, 1.30; 95% CI, 1.15-1.47) or 2 atopic parents (OR, 2.08; 95% CI, 1.83-2.36), as well as having a parent with 1 (OR, 1.49; 95% CI, 1.28-1.74) or more atopic diseases (OR, 2.32; 95% CI, 1.92-2.81).

CONCLUSIONS

This study provides evidence-based risk estimates that may guide physicians who counsel parents with a history of atopic disease about their children's risk of AD. This information is of particular importance for future efforts toward establishing prophylactic interventions for AD on a general population level.

Major allergen content consistency of SQ house dust mite sublingual immunotherapy tablets and relevance across geographic regions

BACKGROUND

Consistency in composition and potency, particularly regarding major allergens, is crucial for the quality of extracts for allergen immunotherapy.

OBJECTIVE

To characterize the major allergen composition of house dust mite (HDM) extracts commercially available in the United States and the SQ HDM sublingual immunotherapy (SLIT) tablet, and to relate the composition to patient sensitization patterns.

METHODS

Der 1/Der 2 ratios were determined in 10,000- and 30,000-AU/mL HDM extracts from 5 US companies and the SQ HDM SLIT-tablet. Allergen content was analyzed by enzyme-linked immunosorbent assay and compared with an in-house reference. Sensitivity toward Der p 1, Der p 2, and Der p 10 was determined in serum from randomly selected subgroups of 220 individuals from North American and European SQ HDM SLIT-tablet trials.

RESULTS

Mean Der 1/Der 2 ratios in US HDM extracts ranged from 0.4 to 20.5. For the SQ HDM SLIT-tablet (20 batches), variability did not exceed 12% regarding content of Der f 1 (SD, 11.9%; 95% confidence interval [CI], 0.94-1.06), Der p 1 (SD, 6.1%; 95% CI, 0.97-1.03), and combined Der 2 allergen (SD, 6.4%; 95% CI, 0.97-1.03), indicating a consistent Der 1/Der 2 ratio. High allergen sensitivity frequencies toward Der p 1 and Der p 2 were observed regardless of geographic region. Efficacy of the SQ HDM SLIT-tablet has been demonstrated in 5 clinical trials.

CONCLUSION

The SQ HDM SLIT-tablet has efficacy potential for a broad range of patients because it includes a consistent 1:1 ratio of the 2 major HDM allergens to which individuals were most frequently sensitized across geographic regions. Efficacy has been demonstrated.

Efficacy Evaluation of a Pollen Blocker Cream against Dust-Mite Allergy: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Crossover Trial

Objective

To further evaluate the efficacy and safety of a pollen blocker cream against dust-mite allergy.

Methods

A multicenter, randomized, double-blind, placebo-controlled, crossover trial was conducted in a Chinese population. Patients diagnosed with perennial allergic rhinitis, sensitive to dust-mite allergy including Dermatophagoides farinae and Dermatophagoides pteronyssinus were randomly allocated to receive a pollen blocker cream or placebo, which was applied and spread evenly to the lower internal nose region three times daily for a total of 30 days. The primary outcome measurements for efficacy were total nasal symptom score (TNSS) and individual nasal symptom score (iNSS). Adverse events were also monitored.

Results

After application of a pollen blocker, the mean TNSS decreased from 23.1 to 13.8, the decrease of the pollen blocker group (9.3) was highly significant compared with the placebo group (5.2; p < 0.001). Similarly, the decreases in iNSSs (rhinorrhea, congestion, sneezing, and itching) between the pollen blocker group and the placebo group were also significant (p < 0.05). In addition, in adults, the pollen blocker led to a remarkably significant decrease in TNSS (9.5) compared with placebo (5.4; p < 0.001); in children, the pollen blocker led to a significant decrease in TNSS (8.6) compared with placebo (4.8; p < 0.05). No statistical difference was found in the incidence of adverse events between the two groups (p > 0.05), and no severe systematic reactions were observed.

Conclusion

Pollen Blocker is a safe and effective alternative to the drugs for treatment of AR, especially for Chinese people allergic to dust-mite allergy.

EFFECT OF NATIVITY AND DURATION OF RESIDENCE ON CHRONIC HEALTH CONDITIONS AMONG ASIAN IMMIGRANTS IN AUSTRALIA: A LONGITUDINAL INVESTIGATION

This study examined the effect of Asian nativity and duration of residence in Australia on the odds of reporting a chronic health condition (cancer, respiratory problems, cardiovascular disease (CVD) and diabetes mellitus). Data were from waves 3, 7 and 9 of the Household Income and Labour Dynamics in Australia (HILDA) longitudinal survey, and multi-level group-mean-centred logistic regression models were used for the analysis. After covariate adjustment, Asian immigrants were less likely to report cancer and respiratory problem compared with native-born Australians. While there was no significant difference in reporting CVD, they were more likely to report diabetes than native-born people. Asian immigrants maintained their health advantage with respect to cancer regardless of duration of residence. However, after 20 years of stay, Asian immigrants lost their earlier advantage and were not significantly different from native-born people in terms of reporting a respiratory problem. In contrast, Asian immigrants were not measurably different from native-born Australians in reporting diabetes if their length of stay in Australia was less than 20 years, but became disadvantaged after staying for 20 years or longer. There was no measurable difference in the odds of reporting CVD between Asian immigrants and native-born Australians for any duration of residence. On the whole this study found that health advantage, existence of healthy immigrant effect and subsequent erosion of it with increasing duration of residence among Asian immigrants depends upon the chronic health condition.

House dust mite allergen levels in households and correlation with allergic rhinitis symptoms

BACKGROUND

House dust mite (HDM) allergen is a risk factor for the development of allergic rhinitis (AR).

OBJECTIVES

To determine the levels of indoor allergens in the households of patients with AR in Wuhan city, identify the environmental risk factors for high allergen exposure, and investigate the correlations between allergen exposure and specific immunoglobulin E levels and symptoms.

METHODS

The study examined 50 patients with AR. Two dust samples were collected from the bedding of each patient, one in summer and one in winter. Major allergens Der p 1 and Der f 1, from Dermatophagoides pteronyssinus and Dermatophagoides farinae, were measured with an enzyme-linked immunosorbent assay. Participants completed a standardized questionnaire about their living environments, and their rhinitis symptom scores were calculated. Specific immunoglobulin E levels against Der p and Der f were measured.

RESULTS

The percentage of bedding samples with high HDM allergen (Der f 1 + Der p 1) levels (>10 μg/g) was 44% in summer and 46% in winter. There was no significant difference between the level of mite allergens in summer and winter; however, the level of Der f 1 was higher than that of Der p 1 (p < 0.05). The age of the mattress and pillow was significantly correlated with allergen concentration. Indoor HDM allergen level affected the severity of nasal itching.

CONCLUSIONS

HDMs are important indoor allergens in Wuhan. Mattresses and pillows that have been used for a long time contain high levels of allergens. High levels of exposure to HDM allergens correlates with the severity of nasal itching.

Group 10 allergens (tropomyosins) from house-dust mites may cause covariation of sensitization to allergens from other invertebrates

Group 10 allergens (tropomyosins) have been assumed to be a major cause of cross-reactivity between house-dust mites (HDMs) and other invertebrates. Despite all of the published data regarding the epidemiology, percent IgE binding and level of sensitization in the population, the role of tropomyosin as a cross-reactive allergen in patients with multiple allergy syndrome still remains to be elucidated. Homology between amino acid sequences reported in allergen databases of selected invertebrate tropomyosins was determined with Der f 10 as the reference allergen. The 66.9 and 54.4% identities were found with selected crustacean and insect species, respectively, whereas only 20.4% identity was seen with mollusks. A similar analysis was performed using reported B-cell IgE-binding epitopes from Met e1 (shrimp allergen) and Bla g7 (cockroach allergen) with other invertebrate tropomyosins. The percent identity in linear sequences was higher than 35% in mites, crustaceans, and cockroaches. The polar and hydrophobic regions in these groups were highly conserved. These findings suggest that tropomyosin may be a major cause of covariation of sensitization between HDMs, crustaceans, and some species of insects and mollusks.

Prevalence and diversity of allergic rhinitis in regions of the world beyond Europe and North America

BACKGROUND

There is comparatively little information in the public domain on the diversity in prevalence and triggers/factors associated with allergic rhinitis (AR) or allergic rhinoconjunctivitis (AR/C) in countries beyond western-Europe and North America.

OBJECTIVE

To review the prevalence and the sensitizing agents/triggers and factors associated with AR/C in several countries in Africa, the Asia-Pacific region, Australia, Eastern Europe, Latin America, Middle East and Turkey.

METHODS

Articles published in English in peer-reviewed journals were assessed and selected for further review, following an extensive literature search using the Medline database.

RESULTS

This review demonstrated that prevalence of AR and AR/C in these regions has predominantly been investigated in children; with studies indicating wide inter- and intra-regional variations ranging from 2.9% AR and 3.8% AR/C in 10-18-years-old children from one region in Turkey to 54.1% AR and 39.2% AR/C in 13-14-years-old children in one region in Nigeria. Moreover, the prevalence of AR and AR/C has increased markedly over the last decade particularly in some of the more affluent African countries, China-Taiwan and several Middle East countries, likely as a consequence of improved living standards leading to increased exposure to multiple traditional and non-traditional sensitizing agents and risk factors similar to those noted in western-Europe and North America.

CONCLUSIONS AND CLINICAL RELEVANCE

Our findings suggest that the greater diversity in prevalence of AR or AR/C in populations in these regions is in contrast to the lower diversity of AR or AR/C in the 'western populations (USA and Europe), which tend to be more uniform. This review provides a comprehensive database of the important allergens and triggers which are likely to influence the prevalence of allergic rhinitis in these diverse regions, where the prevalence of allergic rhinitis is increasing and its adverse impact on the quality of life of affected individuals is increasingly recognised.

[House dust mites and their allergens]

The taxonomy, anatomy, life cycle and ecology of Pyroglyphidae mites and storage mites (Acaridae, Glycyphagidae, B. tropicalis) are described. Pyroglyphidae and storage mites have similar morphologies: they are octopods, with characteristic gnathosoma and sensory hairs. Salivary glands and the mid gut produce most of the allergens excreted, which are enzymatic proteins. Biological cycles and development are similar, although fecundity is superior in storage mites compared to the Pyroglyphides. Relative humidity is the main parameter, which regulates mite development, with a higher degree of temperature and humidity required for storage mites. Bedding is the ecological niche of Pyroglyphidae, which feed on human skin. Moulds and food products are the storage mite biotope from which they spread in the dwelling. Initially considered as rural mites, storage mites are also present in urban dwellings. B. tropicalis, in tropical regions is a true domestic mite. Because of this, it is justified to denominate Pyroglyphidae "house dust mites" and storage mites "domestic mites". In addition to the respiratory allergic symptoms, the storage mites can also cause occupational contact dermatoses.

Increase in asthma and a high prevalence of bronchitis: results from a population study among adults in urban and rural Vietnam

BACKGROUND

While a large amount of data about the epidemiology of asthma, COPD, chronic bronchitis and respiratory symptoms are available from developed countries, the information about these diseases in developing countries in south-east Asia are scarce.

AIM

Assess the prevalence of respiratory diseases and symptoms and their relation with demographic data including smoking habits among adults in rural and urban Vietnam.

METHODS

A random sample of subjects aged 21-70 years were invited; 3008 subjects living in an inner city area of Hanoi and 4000 in a rural area of Bavi in northern Vietnam. An internationally used questionnaire was delivered by field workers to the study subjects. The questionnaire was completed by the subjects, or when necessary, by the field workers after reading the questions for the study participants.

RESULTS

The response rate was 92% in Bavi and 70% in Hanoi. Of men in Bavi 67.8% (Hanoi 49.7%; p < 0.001) were smokers, while of women 4.2% were smokers in Hanoi (Bavi 1.2%; p < 0.001). The prevalence of ever asthma was in Hanoi 5.6% (Bavi 3.9%; p = 0.003) with no major gender difference. The most common symptom was longstanding cough (Hanoi 18.1%, Bavi 12.0%; p < 0.001) followed by sputum production, while the prevalence of symptoms common in asthma was considerably lower. Although the large difference in smoking habits, respiratory symptoms tended to be only slightly more common in men than women. Family history of asthma and chronic bronchitis, respectively, were strongly associated with both diseases.

CONCLUSIONS

The prevalence of asthma in adults may have increased in both urban and rural Vietnam, as the few previous estimates have found 2% of adults having asthma. Half of men in Hanoi and two-thirds in Bavi were smokers versus a few percent of women in both areas. Bronchitic symptoms were common in both men and women.

A multicentre study assessing the prevalence of sensitizations in patients with asthma and/or rhinitis in China

BACKGROUND

The prevalence of sensitization in patients with asthma and rhinitis in mainland China remains unclear.

OBJECTIVE

Our aim was to estimate the prevalence of allergy in patients with respiratory allergic diseases such as asthma and/or rhinitis attending respiratory clinics within mainland China. The study also investigated regional and annual differences in the prevalence and pattern of sensitization among the patients in China.

METHOD

A cross-sectional survey was performed in 6304 patients suffering from asthma and/or rhinitis in 17 cities from 4 regions of China. Patients completed a standardized questionnaire asking for the presence of respiratory and allergic symptoms. They also underwent skin prick tests with 13 common aeroallergens.

RESULTS

Among the 6304 patients, 4545 (72.1%) had at least one positive skin prick reaction. The overall prevalence of positive skin prick responses was 59.0% for Dermatophagoides farinae, 57.6% for Dermatophagoides pteronyssinus, 40.7% for Blomia tropicalis, 16.1% for American cockroach, 14.0% for dog, 11.5% for Blatella germanica, 11.3% for Artemisia vulgaris, 10.3% for cat, 6.5% for Ambrosia artemisifolia, 6.3% for mixed mould I, 4.4% for mixed mould IV, 3.5% for mixed grass pollen and 2.2% for mixed tree pollen. Sensitizations to common allergens varied widely between geographical areas and demonstrated unique pattern in patients by stratification with age groups, with asthma and/or rhinitis. Severity of rhinitis and asthma was significantly correlated with skin index of reactivity to Artemisia vulgaris, Ambrosia artemisifolia and to D. pteronyssinus, D. farinae and Blomia tropicalis respectively (P < 0.001). Positive reactivity to the tested allergens and concomitant reactivity to multiple allergens including to house dust mites and Blomia tropicalis was markedly increased in patients with both asthma and rhinitis.

CONCLUSION

House dust mites were the most prevalent allergens in patients with asthma and/or rhinitis in China. There were significant differences in patterns of sensitizations in patients from different geographical areas, age groups as well as asthma and/or rhinitis.

Occupational health risks due to shipboard cockroaches

OBJECTIVES

In various investigated populations, sensitization to cockroaches was observed in 8% of screened subjects from temperate climatic zones and in 36% of those from tropical zones. Because of the numerous hiding places and food storages aboard a ship the crews can be highly exposed to cockroaches. The aim of this study is to assess the prevalence of sensitization to cockroaches and potentially associated health risks in seafarers.

METHODS

In July 2005, a total of 145 seamen sailing under the German flag were recruited from a medical surveillance program for a cross-sectional study (response 95.4%). A standardized interview and a skin prick test (SPT) with nine common inhalant allergens and a cockroach extract (Blatella germanica) were performed. In cockroach-sensitized seafarers total and cockroach-specific IgE was measured and lung function tests conducted.

RESULTS

In total, 39 seamen (26.9%) were cockroach-sensitized according to SPT results. Presence of cockroach sensitization in seamen from the tropical zone (37.3%) was significantly higher than in seamen from the temperate zone (21.3%) (odds ratio 2.20, 95% confidence interval 1.04-4.66). The prevalence of sensitization to any of the other nine common allergen mixtures tested was lower (between 2.1 and 12.4%). Neither current or past cockroach exposure on board nor cumulative cockroach exposure and time since last cockroach exposure were associated with cockroach sensitization. Among cockroach SPT-positive seamen, cockroach-specific IgE was detected in 52.8%. Five out of 37 (13.5%) SPT-positive seamen exhibited an obstructive ventilation pattern. The prevalence of work-related atopic symptoms was 9.0% (n = 13). These symptoms were not related to cockroach sensitization.

CONCLUSION

The high prevalence of sensitization to cockroaches among seamen in the presented study emphasizes the strong sensitization potency of these insects. Longitudinal studies and bronchial cockroach challenge tests are necessary to assess the clinical relevance of cockroach sensitization aboard a ship in more detail.

Indoor allergens, asthma, and asthma-related symptoms among adolescents in Wuhan, China

PURPOSE

Information on indoor allergen exposures among non-Western populations, which have lower prevalence of atopic illness, is scant. We examined whether exposures to common indoor allergens were associated with doctor-diagnosed asthma and asthma-related symptoms among Chinese adolescents.

METHODS

A cross-sectional study of 4,185 ninth grade students was conducted at 22 randomly selected schools in Wuhan, China. Information on respiratory health and exposures to indoor allergens was obtained by a self-administered questionnaire completed in class.

RESULTS

Having animals currently was associated with persistent cough [prevalence odds ratio (POR)=1.54, 95% confidence interval (CI ): 1.21-2.11] and wheeze (POR=1.41, 95% CI: 1.03-1.94). Early-life exposure to animals was also associated with doctor-diagnosed asthma (POR=1.95, 95% CI: 1.35-2.82). Associations with respiratory symptoms strengthened with higher levels of exposure and for exposure in both early childhood and in adolescence. Exposure to cockroaches and having mold/water damage in the home contributed especially to wheezing (POR=2.03, 95% CI: 1.41-2.90 for cockroaches; POR=2.49, 95% CI: 1.82-3.40 for mold/water damage).

CONCLUSIONS

Indoor allergen exposures were positively associated with asthma diagnosis and persistent respiratory symptoms among Chinese adolescents. Neither early-life nor current exposure to animals was protective for asthma or asthma-related symptoms.

Respiratory symptoms in relation to residential coal burning and environmental tobacco smoke among early adolescents in Wuhan, China: a cross-sectional study

BACKGROUND

Cigarette smoking and coal burning are the primary sources of indoor air pollution in Chinese households. However, effects of these exposures on Chinese children's respiratory health are not well characterized.

METHODS

Seventh grade students (N = 5051) from 22 randomly selected schools in the greater metropolitan area of Wuhan, China, completed an in-class self-administered questionnaire on their respiratory health and home environment.

RESULTS

Coal burning for cooking and/or heating increased odds of wheezing with colds [odds ratio (OR) = 1.57, 95% confidence interval (CI): 1.07-2.29] and without colds (OR = 1.44, 95% CI: 1.05-1.97). For smoking in the home, the strongest associations were seen for cough (OR = 1.74, 95% CI: 1.17-2.60) and phlegm production (OR = 2.25, 95% CI: 1.36-3.72) without colds among children who lived with two or more smokers.

CONCLUSIONS

Chinese children living with smokers or in coal-burning homes are at increased risk for respiratory impairment. While economic development in China may decrease coal burning by providing cleaner fuels for household energy use, the increasing prevalence of cigarette smoking is a growing public health concern due to its effects on children. Adverse effects of tobacco smoke exposure were seen despite the low rates of maternal smoking (3.6%) in this population.

[Prevalence of atopic dermatitis in schoolchildren from Cartagena (Spain) and relationship with sex and pollution]

BACKGROUND

Atopic dermatitis is favored by exogenous factors, such as air pollution interacting with a genetic predisposition.

OBJECTIVE

The aim of the present study was to evaluate the influence of sex and air pollution in the city of Cartagena on the prevalence of atopic dermatitis.

DESIGN AND METHODS

We performed a cross-sectional study using the ISAAC questionnaire in schoolchildren aged 13 and 14 years old from Cartagena (Murcia). The influence of sex and the schools' location in two distinct areas (polluted and unpolluted) on the prevalence of atopic dermatitis and its severity (described as being awakened by nocturnal itching) was analyzed.

RESULTS

The prevalence of atopic eczema was 6.3 %. Atopic eczema was severe in 19 % of the cases. Risk factors for atopic eczema were female sex (OR 2.19 95 % CI: 1.59-3. 02) and attending school in a polluted area (OR: 1.83, 95 % CI 1.01-1.87) but these factors were not associated with greater severity.

CONCLUSIONS

Air pollution is associated with a higher prevalence of atopic eczema and there is a trend that this eczema is more severe. The condition was more prevalent among girls.

Methodologic aspects of the quantification of skin prick test responses: the EGEA study

BACKGROUND

The expression of responses of allergy skin prick tests is not standardized. Usual definitions of atopy are not quantitative.

OBJECTIVE

We sought to perform a biometric analysis of responses to various allergens to propose synthetic, quantitative indices independent of the heterogeneity of responses to various allergens.

METHODS

Adults (N = 1286) from the Epidemiological Study on the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy (EGEA) were included in the analysis. The first step, conducted for 678 subjects with at least 1 wheal >0, was to perform a standardization of wheal diameters to obtain comparable figures for 10 allergens through use of the means of the squares of wheal size as a scaling factor. The second step was a factor analysis of the standardized responses conducted not only for all subjects but also separately for asthmatic case and nonasthmatic control subjects. Finally, the strength of the link between various dichotomous and quantitative scores was assessed with multiRAST, total IgE, and asthma. Analyzed quantitative scores were based on the number of positive responses and on the nonstandardized and standardized sizes of the wheals.

RESULTS

The standardization was efficient. Among asthmatic subjects but not other subjects, factor analysis evidenced a pattern with 3 factors, corresponding to outdoor, indoor, and mold allergens. The link study showed that all scores performed very similarly.

CONCLUSION

The number of positive tests is a quantitative score with valid biometric properties. It should be used more widely in clinical settings and in epidemiology to assess the severity of atopy.

Analysis of the C314T and A595G mutations in histamine N-methyltransferase gene in a Chinese population

BACKGROUND

Histamine N-methyltransferase (HNMT) plays an important role in the metabolism of histamine, a biogenic amine that has many physiologic and pathological roles in human tissues. A missense mutation C314T (Thr105Ile) in the HNMT gene has been identified to represent a common functional polymorphism in Caucasians, whereas an A595G (Ile199Val) variant has been reported in one HNMT cDNA from a Japanese subject.

METHODS

By using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay, the point mutations C314T and A595G within HNMT were both detected in 352 unrelated Chinese Han subjects.

RESULTS

None of the 352 subjects contained the A595G mutation, whereas 40 (11.6%) heterozygotes and 1 (0.3%) homozygote for the variant T314 allele were detected. The frequency of the variant T314 allele in this Chinese population was 0.060 (95% CI: 0.042-0.078), not different from Japanese but significantly lower than American Caucasians.

CONCLUSIONS

The C314T mutation represents a common functional genetic polymorphism in the Chinese Han population with a variant T314 allele frequency similar to Japanese but lower than American Caucasians, whereas the A595G mutation does not appear to exist in this population.

Ascaris lumbricoides infection is associated with increased risk of childhood asthma and atopy in rural China

There is growing international interest in the possible relationships between helminthic infection and allergic disease, although the nature of the relationships remains uncertain and controversial. The interrelationships of current and past infection with Ascaris lumbricoides and asthma and atopy were investigated in a cross-sectional sample of 2,164 children between the ages of 8 and 18 years from Anqing Province, China. The children were sampled from a larger family-based study of the genetics of asthma. The prevalence of either a history of or a positive stool examination for Ascaris was 24.5%. Asthma was defined for analytic purposes using previously validated, stringent criteria including airways responsiveness to methacholine. Independently of the other factors assessed, infection with A. lumbricoides was associated with increased risk of asthma (p < 0.001), an increased number of skin tests positive to aeroallergens (p < 0.001), and an increased dose-response slope to methacholine (p = 0.003). The association of sensitization to common aeroallergens with increased asthma risk was enhanced in those children infected with Ascaris, and such infection was associated with an increased risk of asthma independent of sensitization to aeroallergens in this selected population. These data suggest a complex relationship between ascariasis and susceptibility to childhood asthma among predisposed children that may involve an interaction with the immune response to inhaled aeroallergens.

Involvement of urban living environments in atopy and enhanced eosinophil activity: potential risk factors of airway allergic symptoms

BACKGROUND

Airway allergic diseases, such as bronchial asthma and allergic rhinitis, have increased, especially in urban areas. These diseases are characterized by airway inflammation with enhanced eosinophil activity, and the risk of disease development has been shown to increase with the prevalence of atopy.

METHODS

Questionnaires were administered to 426 healthy adult women aged 30-74 years, living in an urban area of Osaka, Japan, to survey individual living environments and airway allergic symptoms such as cough, sputum, and wheezing. Moreover, serum house-dust-mite (Dermatophagoides pteronyssinus, [Der p])-specific immunoglobulin E (IgE) and serum eosinophil cationic protein (ECP) were examined by radioimmunoassay, and the atopic status (atopic sensitization) and enhanced eosinophil activity were assessed as Der p-specific IgE RAST scores of 2-6 and ECP levels of more than 10 ng/ml, respectively.

RESULTS

Intensive use of electric air conditioners in hot weather (odds ratio: 2.07 [95% CI: 1.11-3.87]) and mold proliferation in the kitchen (2.77 [1.34-5.73]) significantly increased the risk of atopic sensitization. Poor home ventilation and family smoking appeared to be positively but not significantly associated with atopic sensitization. Personal smoking and intensive use of the air conditioner appeared to be positively related to enhanced eosinophil activity. Atopic status showed significant involvement in the development of wheezing, and the development of cough was significantly associated with enhanced eosinophil activity.

CONCLUSIONS

The results suggest that some urban styles of living are involved in atopic sensitization and enhanced eosinophil activity in the Japanese urban population, probably due to living conditions, such as indoor dampness and poor home ventilation, caused by tight insulation, which increase exposure to indoor air pollutants, such as respirable mite allergens and tobacco smoke.

Prevalence of allergic rhinitis and atopic dermatitis among children in four regions of Finland

The primary aim of the study was to evaluate the prevalences of allergic rhinitis and atopic dermatitis and their regional differences among Finnish children. The secondary objective was to determine whether the responses to the questions used are affected by the pollen season if asked during such a season. In 1994-5, the self-reported prevalence of allergic symptoms in four regions of Finland was studied among 11,607 schoolchildren aged 13-14 years, as part of the International Study of Asthma and Allergies in Childhood (ISAAC). The prevalence of rhinoconjunctivitis during the preceding year was 16% in eastern Finland (Kuopio County, n=2821), 23% in southern Finland (Helsinki area, n=2771), 15% in southwestern Finland (Turku and Pori County, n=2983), and 16% in northern Finland (Lapland, n=3032). The respective prevalences of flexural dermatitis were 15%, 19%, 16%, and 18%. The surveys were performed in winter, except in the Helsinki area where the survey was carried out mainly in the spring pollen season. Among the children studied in autumn in Helsinki, the prevalence of rhinoconjunctivitis was 19% and that of flexural dermatitis 17%. In multivariate analysis, flexural dermatitis was slightly more common in Lapland than in all other areas. In contrast, no significant differences were found in rhinoconjunctivitis. The prevalences of both disorders were twice as high in girls as in boys. In conclusion, regional differences in the prevalence of allergic rhinitis and atopic dermatitis were small in our country, and the prevalence figures were rather similar to those reported from other European countries. Almost half of the children had suffered from at least one atopic disorder, and over one-third had had symptoms in the past year. A clear season-of-response effect was observed; the prevalence of rhinoconjunctivitis was 25% when studied during the pollen seasons in the Helsinki area.

Prevalence of childhood asthma based on questionnaires and methacholine bronchial provocation test in Korea

BACKGROUND

In most epidemiological survey studies, only subjective symptoms and past medical history of asthma have been used as diagnostic criteria. Even though a questionnaire survey can be performed in a large population study at low cost, limitations such as lack of objectivity and poor predictability in non-specific bronchial hyperresponsiveness cannot be avoided.

OBJECTIVES

The purpose of this study was to elucidate the prevalence of current asthma based on questionnaires and methacholine bronchial provocation test, and the prevalence of atopy in Korea.

METHODS

We performed modified ATS respiratory questionnaires and allergen skin-prick test with 10 common inhalant allergens among 3219 subjects aged 7-19 years in Seoul and a rural part of a small city, Chungju in Korea. Methacholine bronchial provocation tests were also performed among those who had asthma symptoms according to the questionnaire. The criteria of asthma was presence of both asthma symptoms and non-specific bronchial hyperresponsiveness. Atopy was defined as when an allergen induced weal size is same or larger than that caused by histamine.

RESULTS

The prevalence of asthma based on questionnaires and methacholine bronchial provocation tests was 4.6%, while the prevalence of wheeze was 8.2% and 19.3% of total population complained of one or more respiratory symptoms related to asthma on the questionnaires. There was no significant difference according to age, sex and living area. The mean prevalence of atopy was 35.0% and the most common allergens were Dermatophagoides farinae (30.9%), Dermatophagoides pteronyssinus (27.5%), cat fur (20.4%) and cockroach (11.8%). The atopy prevalence in Chungju area was higher than that in Seoul and males showed a higher prevalence than females. The asthma prevalence was higher among atopics (6.8%) than among non-atopics (2.7%). None of questionnaire items were enough to predict the presence of bronchial hyperresponsiveness in terms of sensitivity, specificity and positive predictive value.

CONCLUSION

The prevalence rate of current asthma in Korea was 4.6% and the prevalence rate of atopy in Korea was 35.0%. Questionnaire-based surveys are not enough to predict the actual prevalence of asthma.

Prevalence of asthma, rhinitis and eczema among schoolchildren in Kelantan, Malaysia

The prevalence and severity of asthma, rhinitis and eczema in Kelantanese schoolchildren were determined as part of an international study of the epidemiology of asthma and allergic diseases. The international study of asthma and allergies in childhood (ISAAC) written questionnaire was administered to 7055 schoolchildren from February 1995 to August 1995. The respondents were parents or guardians of 5- to 7-year-old children (n = 3939), and schoolchildren aged 12-14 years (n = 3116). The ISAAC video questionnaire (AVQ3.0) was shown to children aged 12-14 years after the written questionnaire. The overall prevalences of 'ever wheezed' and 'wheezing in last 12 months' were 9.4 and 6.0% respectively. The prevalence of 'ever diagnosed with asthma' was 9.4%. Both 'ever wheezed' and 'wheezing in the last 12 months' were significantly higher in 12- to 14-year-old children than in 5- to 7-year-old children, with P values of 0.0006 and 0.014 respectively. No gender differences in the prevalences were observed. For the complete study group, 4.7% of children had sleep disturbed by wheezing but only 1.1% had a severe attack limiting speech in the preceding 12 months. Sleep disturbance was more common in the 12- to 14-year-old children than in 5- to 7-year-old children (P = 0.006). There was no difference between the age groups for severe attacks limiting speech. The overall prevalence of rhinitis and eczema symptoms were 27 and 12%, respectively. The prevalence of rhinitis in the 12-14 year age group (38.2%) was significantly higher (P < 0.0001) than in the 5-7 year age group (18.2%). The prevalence of eczema in the 5-7 year age group (13.7%) was significantly higher (P = < 0.0001) than in the 12-14 year age group (9.9%). These prevalence data are comparable with previous reports in Malaysian children, but are considerably lower than those reported for most developed countries.

Exercise induced bronchospasm in Ghana: differences in prevalence between urban and rural schoolchildren

BACKGROUND

As more developing countries adopt a westernised style of living, an increase in the prevalence of asthma can be expected to occur in these areas. A study was undertaken to establish the normal response to exercise in Ghanaian children and to use these normal values to determine the prevalence of exercise induced bronchospasm (EIB) in urban rich (UR), urban poor (UP), and rural (R) school children. Skin test reactivity to common inhalant allergens in UR, UP, and R children with and without EIB was also investigated.

METHODS

Two hundred children aged 9-16 years without a previous history of respiratory symptoms were randomly selected and underwent free running exercise testing. A normal response to exercise was defined as the group mean change in peak expiratory flow rate (PEFR) +/- 2 standard deviations. This value was used to identify the prevalence of EIB in UR, UP, and R schoolchildren. A total of 1095 children from three different schools underwent exercise testing (220 UP, 599 UR, 276 R), after which 916 children underwent skin prick testing to six common inhalant allergens (D farinae, D pteronyssinus, cat, dog, Aspergillus flavus and Candida albicans).

RESULTS

From the results of exercise testing in asymptomatic children the normal range was defined as a fall in PEFR of < 12.5% after exercise. Thirty four children were classified as having EIB on the basis of the above definition, giving an overall prevalence of 3.1%. The prevalence of EIB was significantly higher in UR children (4.7%) than in both UP (2.2%; p < 0.05) and R children (1.4%; p < 0.01). However, the prevalence rates in the UP and R children were similar. The prevalence of atopy in the whole population was 4.4%. Of the children with EIB, 10% were skin test positive to at least one of the allergens tested. The prevalence of atopy was significantly higher in UR children (6.55%, 95% confidence interval (CI) 4.5% to 9.2%) than in UP (2.9%, 95% CI 0.9% to 6.7%) and R children (1.5%, 95% CI 0.4% to 3.7%), respectively (p < 0.005).

CONCLUSIONS

The prevalence of EIB and atopy is higher in urban rich than in urban poor or rural children suggesting that, in addition to genetic predisposition, social and environmental factors such as wealth, life style, and housing are important determinants of these phenotypes.

Epidemiology of allergic diseases

The escalation of allergic diseases (hay fever, asthma, atopic eczema) over recent decades has been linked to an increase in environmental pollutants. The prevalence of hay fever is associated with genetic predisposition, and some reports show an association with urban areas, socioeconomic status, and combined high allergen and automobile exhaust exposure. In asthma, there is also some evidence for geographical variations in prevalence; exercise challenge tests prove positive more often in urban areas than in rural areas. Although genetic predisposition is the strongest single risk factor for atopic eczema, air pollutants may aggravate the condition by acting as unspecific irritants and immunomodulators, leading to increased immunoglobulin E expression. In a study of 678 pre-school children, the influence of maternal smoking habits on individual measures of atopy revealed a positive association between smoking during pregnancy/lactation, and a positive history of atopic eczema. An East-West German comparative study examining different types and levels of air pollution, i.e. sulphurous (industrial; East) and oxidising (urban; West), showed that the prevalence of atopic eczema was greatest in East Germany. When various direct and indirect parameters of air pollution exposure were measured, the greatest association with atopic eczema was found with NOx exposure (indoor use of gas without a cooker hood), and close proximity to roads with heavy traffic. The increased prevalence of atopic eczema cannot be explained by changes in study methodology over time, or conventional risk factors alone; environmental risk factors may be an important contributing factor.

Asthma and migration

The dramatic influx of immigrants from South-East Asian countries into Australia over the past 20 years was associated with an increase is asthma and allergic disease amongst these immigrants. Epidemiological data showed that the prevalence rates of asthma and allergic disease increased with the duration of residence in Australia so that after 10 years in Australia, up to 60% of South-East Asian immigrants developed hayfever while 15% had symptoms of asthma. Many immigrants developed these conditions for the first time after arrival in Australia suggesting that the environment plays a important role in the pathogenesis of asthma and allergy. While sensitization to inhalant allergens such as house dust mite and grass pollen are apparently important in some, other yet undefined local factors are likely to contribute significantly to the overall increase in prevalence. A prospective study designed to follow a group of migrants in areas where asthma and allergic disease are common such as Australia, may reveal the pathogenic role of the environment and provide valuable information that may explain the global distribution and increasing trend of asthma and allergies.

Prevalence and severity of asthma, rhinitis, and eczema in Singapore schoolchildren

This study was part of an international effort to evaluate the epidemiology of asthma and allergic diseases around the world. The aim was to assess the prevalence and severity of these disorders in Singapore schoolchildren. The international study of asthma and allergies in childhood (ISAAC) written questionnaire was administered to 6238 schoolchildren. The respondents were parents of a 6-7 year cohort (n = 2030), and schoolchildren aged 12-15 years (n = 4208). The overall cumulative and 12 month prevalence of wheezing were 22% and 12%, respectively. The prevalence of doctor diagnosed asthma was 20%. Rhinitis was reported by 44% and chronic rashes by 12%. Multiple logistic regression analysis showed that a higher prevalence of wheezing and rhinitis was associated with males, and subjects of higher socioeconomic status (based on type of housing and total family income). More severe asthma related symptoms were present in Malays and Indians than in the Chinese. Allergic disorders are common in Singapore and prevalence is comparable to some populations in the West. Demographic and socioeconomic factors appear to influence the prevalence and severity of these disorders.

Prevalence and severity of childhood asthma and allergic sensitisation in seven climatic regions of New South Wales

OBJECTIVE

To compare the prevalence and severity of asthma and of allergic sensitisation in children in different regions. We hypothesised that regions with different standardised hospital admission rates would have different prevalences of childhood asthma and that diverse climates would result in a range of sensitisations to different allergens.

DESIGN AND SETTING

We studied large random population samples of children in seven regions in New South Wales (NSW) in 1991-1993. Hospitalisation rates were obtained from NSW Department of Health data.

PARTICIPANTS

6394 children aged 8-11 years.

OUTCOME MEASURES

History of respiratory symptoms by self-administered questionnaire; airway hyperresponsiveness by histamine inhalation test; and sensitisation to allergens by skin-prick tests.

RESULTS

Children in all regions had a high prevalence of recent wheeze (22%-27%), of diagnosed asthma (24%-38%) and of use of asthma medications (22%-30%), but no region was consistently higher or lower for all measurements. The prevalence of current asthma in children living in three coastal regions (where sensitisation to house-dust mites was high) and in the far west (where sensitisation to alternaria was high) was 12%-13%, which was significantly higher than the prevalence of 7%-10% in children living in three inland regions (where sensitisation to these allergens was lower) (P < 0.01).

CONCLUSIONS

We found significant variations in the prevalence and severity of childhood asthma in NSW. The prevalence of hospitalisations, diagnosed asthma, recent symptoms and medication use may relate to different regional diagnostic patterns, whereas current asthma prevalence may relate to different levels of allergic sensitisation.

Asthma, allergy, and atopy in three south-east Asian populations

BACKGROUND

Whilst many recent reports have suggested a rise in the prevalence of asthma and allergic disease in Western countries, little is known about the epidemiology of these common conditions in south-east Asia. This study compared the prevalence of asthma and allergic disease amongst secondary school students in three south-east Asian populations--Hong Kong, Kota Kinabalu in Malaysia, and San Bu in China--and investigated the associations with atopy and family history.

METHODS

Secondary school students were given standard questionnaires on respiratory and allergic symptoms for completion by parents with response rates of 89.2% in Hong Kong (611 male, 451 female; mean (SD) age = 13.9 (1.8 years), 87.6% in Kota Kinabalu (134 male, 275 female; 15.5 (2.1) years), and 98.6% in San Bu (492 male, 245 female; 16.4 (1.8) years). Skin tests were performed in a subsample of students to determine atopic status.

RESULTS

The respective prevalence (and 95% CI) for hayfever, eczema, and wheeze or asthma were 15.7% (13.5, 17.9), 20.1% (17.7, 22.5), 11.6% (9.3, 13.9) in Hong Kong, 11.2% (8.2, 14.3), 7.6% (5.0, 10.1), 8.2% (5.5, 10.9) in Kota Kinabalu, and 2.1% (1.2, 3.1), 7.2% (5.4, 9.1), 1.9% (0.7, 3.1) in San Bu. Atopy was common and was present in 49.0-63.9% of subjects in the three populations. Dust mite and cockroach were the commonest allergens that gave positive reactions in 42.8-60.5% and 25.7-35.9% of students respectively. A higher proportion of students in Hong Kong had severe degree of reactivity on skin test than the other two populations. Family history was associated with asthma and allergic symptoms in the three populations conferring a 3-80-fold increase in risk to family members and was a stronger predictor for asthma and allergy than atopy.

CONCLUSIONS

Prevalence of asthma and allergic disease is low compared with Western countries, but considerable differences exist between the three south-east Asian populations despite similar rates of atopy. Asthma and allergic disease are more strongly associated with family history than atopy, which suggests that genetic and environmental factors common to the family, other than aeroallergen sensitisation, are important in the pathogenesis of asthma and allergy in the region.

Asthma, allergy and atopy in Asian immigrants in Melbourne

OBJECTIVES

To compare the prevalence of asthma, hay fever and atopy in Asian immigrants in Melbourne with that in Australian-born non-Asians and Australian-born Asians, and to investigate the association of these conditions with atopic status, length of stay in Australia and IgE levels in Asian immigrants.

DESIGN

We performed a cross-sectional study by telephone interviews, using standard questionnaire items on respiratory and allergic symptoms. A random sample of 636 recent Asian immigrants of ethnic Chinese origin, 109 Australian-born Asians and 424 Australian-born non-Asians were selected from the 1991 Melbourne Telephone Directory, using a presumptive surname list. Skin tests to determine atopic status were performed on 269 Asian immigrants and 167 of these also had serum levels of total and specific IgE estimated.

RESULTS

In the under 20 years age group the prevalence of wheeze or asthma ever was higher in Australian-born non-Asians and Australian-born Asians than in Asian immigrants (P < 0.001), and the prevalence of hay fever was higher in Asian immigrants and Australian-born Asians than in Australian-born non-Asians. In those older than 20 years, hay fever was almost twice as common in Asian immigrants as in Australian-born non-Asians (P < 0.001 for 20-40 years age group; P < 0.01 for > 40 years). The prevalence of hay fever and, to a lesser degree, asthma in Asian immigrants increased significantly with length of stay in Australia, independent of age at arrival, sex and atopic status (trend test: P < 0.001 for hay fever; P = 0.05 for asthma). Atopy was more common in Asian immigrants and Australian-born Asians than in Australian-born non-Asians (P < 0.001) and was very strongly associated with both hay fever and asthma, irrespective of length of stay. Pollen and mite sensitivities were more common in Asian subjects (twice as common for Asian-born and 1.5 times for Australian-born) than non-Asian subjects (P < 0.01). Among Asian immigrants, elevated total IgE level (> 100 IU/mL) was strongly associated with a history of hay fever (P < 0.01) and wheeze or asthma ever (P < 0.05), atopy (P < 0.001) and the presence of specific IgE antibodies to grass pollen, dust mite, cockroach and Ascaris antigens (P < 0.05 for all).

CONCLUSION

We found substantial differences in the prevalence of asthma, hay fever and atopy between Asian immigrants, Australian-born Asians and non-Asians. The prevalence of hay fever and asthma in Asian immigrants was strongly associated with length of stay in Australia, suggesting that environmental factors are important in the pathogenesis of these diseases.