A family study of the genetic basis of asthma and wheezy bronchitis

Novel Comprehensive Bioinformatics Approaches to Determine the Molecular Genetic Susceptibility Profile of Moderate and Severe Asthma

Background: Asthma is a chronic inflammatory condition linked to hyperresponsiveness in the airways. There is currently no cure available for asthma, and therapy choices are limited. Asthma is the result of the interplay between genes and the environment. The exact molecular genetic mechanism of asthma remains elusive. Aims: The aim of this study is to provide a comprehensive, detailed molecular etiology profile for the molecular factors that regulate the severity of asthma and pathogenicity using integrative bioinformatics tools. Methods: The GSE43696 omnibus gene expression dataset, which contains 50 moderate cases, 38 severe cases, and 20 healthy controls, was used to investigate differentially expressed genes (DEGs), susceptible chromosomal loci, gene networks, pathways, gene ontologies, and protein–protein interactions (PPIs) using an intensive bioinformatics pipeline. Results: The PPI network analysis yielded DEGs that contribute to interactions that differ from moderate-to-severe asthma. The combined interaction scores resulted in higher interactions for the genes STAT3, AGO2, COL1A1, CLCN6, and KSR for moderate asthma and JAK2, INSR, ERBB2, NR3C1, and PTK6 for severe asthma. Enrichment analysis (EA) demonstrated differential enrichment between moderate and severe asthma phenotypes; the ion transport regulation pathway was significantly enhanced in severe asthma phenotypes compared to that in moderate asthma phenotypes and involved PER2, GCR, IRS-2, KCNK7, KCNK6, NOX1, and SCN7A. The most enriched common pathway in both moderate and severe asthma is the development of the glucocorticoid receptor (GR) signaling pathway followed by glucocorticoid-mediated inhibition of proinflammatory and proconstrictory signaling in the airway of smooth muscle cell pathways. Gene sets were shared between severe and moderate asthma at 16 chromosome locations, including 17p13.1, 16p11.2, 17q21.31, 1p36, and 19q13.2, while 60 and 48 chromosomal locations were unique for both moderate and severe asthma, respectively. Phylogenetic analysis for DEGs showed that several genes have been intersected in phases of asthma in the same cluster of genes. This could indicate that several asthma-associated genes have a common ancestor and could be linked to the same biological function or gene family, implying the importance of these genes in the pathogenesis of asthma. Conclusion: New genetic risk factors for the development of moderate-to-severe asthma were identified in this study, and these could provide a better understanding of the molecular pathology of asthma and might provide a platform for the treatment of asthma.

A genome-wide survey of CD4(+) lymphocyte regulatory genetic variants identifies novel asthma genes

BACKGROUND

Genome-wide association studies have yet to identify the majority of genetic variants involved in asthma. We hypothesized that expression quantitative trait locus (eQTL) mapping can identify novel asthma genes by enabling prioritization of putative functional variants for association testing.

OBJECTIVE

We evaluated 6706 cis-acting expression-associated variants (eSNPs) identified through a genome-wide eQTL survey of CD4(+) lymphocytes for association with asthma.

METHODS

eSNPs were tested for association with asthma in 359 asthmatic patients and 846 control subjects from the Childhood Asthma Management Program, with verification by using family-based testing. Significant associations were tested for replication in 579 parent-child trios with asthma from Costa Rica. Further functional validation was performed by using formaldehyde-assisted isolation of regulatory elements (FAIRE) quantitative PCR and chromatin immunoprecipitation PCR in lung-derived epithelial cell lines (Beas-2B and A549) and Jurkat cells, a leukemia cell line derived from T lymphocytes.

RESULTS

Cis-acting eSNPs demonstrated associations with asthma in both cohorts. We confirmed the previously reported association of ORMDL3/GSDMB variants with asthma (combined P = 2.9 × 10(-8)). Reproducible associations were also observed for eSNPs in 3 additional genes: fatty acid desaturase 2 (FADS2; P = .002), N-acetyl-α-D-galactosaminidase (NAGA; P = .0002), and Factor XIII, A1 (F13A1; P = .0001). Subsequently, we demonstrated that FADS2 mRNA is increased in CD4(+) lymphocytes in asthmatic patients and that the associated eSNPs reside within DNA segments with histone modifications that denote open chromatin status and confer enhancer activity.

CONCLUSIONS

Our results demonstrate the utility of eQTL mapping in the identification of novel asthma genes and provide evidence for the importance of FADS2, NAGA, and F13A1 in the pathogenesis of asthma.

Toxocara seropositivity in Sri Lankan children with asthma

BACKGROUND

Toxocariasis occurs in humans due to infection with Toxocara canis or T. cati, the nematode parasites of dogs and cats, respectively. The relationship between toxocariasis and asthma is complex, with some studies demonstrating that children with asthma were more likely to be Toxocara seropositive as compared to non-asthmatic children, and other studies indicating no such significant relationship. The aim of the present study was to investigate Toxocara seropositivity and its association with asthma in a selected group of Sri Lankan children.

METHODS

Two groups of children were studied: group 1 included 100 children with confirmed bronchial asthma who were on regular inhaler steroid treatment for asthma; group 2 included 96 children who did not have physician-diagnosed asthma or upper respiratory tract infections, attending the same hospital. Diagnosis of Toxocara seropositivity was based on IgG Toxocara Microwell Serum Elisa Kits. Enzyme-linked immunosorbent assay was regarded as positive for a reading of 0.3 optical density units. Stool samples were examined for helminth ova.

RESULTS

Toxocara seropositivity in children with asthma was 29% and this was significantly more than Toxocara seropositivity among non-asthmatic children (P < 0.001). Toxocara seropositivity was identified as a significant risk factor of asthma in a univariate model. Eosinophilia was seen in a significantly higher proportion of non-asthmatic and asthmatic children who were Toxocara seropositive. Toxocara seropositivity, however, was not identified as a significant risk factor in a multivariate model.

CONCLUSIONS

The analysis confirmed previously identified risk factors for asthma but there was no association between the helminth parasitic infection, toxocariasis and bronchial asthma in children.

Autologous serum skin test for autoantibodies is associated with airway hyperresponsiveness in patients with asthma

BACKGROUND

Autoimmune diseases have been implicated as a cause of intrinsic asthma; however, there is little data on the role of autoimmunity in the pathogenesis of asthma.

OBJECTIVE

The purpose of this study was to investigate circulating functional autoantibodies against the high-affinity IgE receptor FcepsilonRI or IgE in patients with asthma.

METHODS

Twenty-eight patients with asthma and 19 control subjects were included. All subjects were skin tested with autologous serum to assess for the potential presence of receptor FcepsilonRI or IgE autoantibodies. If the serum-induced wheal diameter was 1.5 mm larger than the histamine-induced wheal diameter and that was 3 mm larger than the saline-induced wheal diameter at 30 min, the reaction was defined positive.

RESULTS

Of the 47 total subjects (both asthma patients and control subjects), 13 (27.7%) had a positive autologous serum skin test (ASST). Of the 28 asthma patients, 8 (28.6%) were regarded as having autoimmune origin. Autoantibodies against FcepsilonRI or IgE were found in asthma patients, irrespective of atopic status (atopy+ 3/13 vs. atopy- 5/15). The wheal diameter related to ASST was not related to atopy. Asthma patients with ASST-positive results as compared with patients with ASST-negative results exhibited a significant increased airway hyperresponsiveness (PC(20) methacholine, 2.70 +/- 1.27 vs. 9.08 +/- 2.35; p < 0.026).

CONCLUSION

Our data demonstrate that aberrant autoantibodies against the high-affinity IgE receptor FcepsilonRI or IgE are related to airway hyperresponsiveness in patients with asthma.

Association between a polymorphism in cysteinyl leukotriene receptor 2 on chromosome 13q14 and atopic asthma

OBJECTIVE

Cysteinyl leukotriene receptor 2 (CYSLTR2) is one of the receptors for the cysteinyl leukotrienes (CYSLTs), which cause bronchoconstrictions, vascular hyperpermeability and mucus hypersecretion in asthmatic patients. CYSLTR1 antagonists have been shown to be effective in the treatment of chronic asthma. CYSLTR2 is located approximately 300 kb from D13S153, which is reportedly linked to asthma in several populations. We characterized the genomic structure of humans CYSLTR2, determined the putative major promoter region and conducted association studies pertaining to polymorphisms in CYSLTR2 and asthma.

METHODS AND RESULTS

We identified three novel exons in the 5' untranslated region of CYSLTR2 by rapid amplification of cDNA ends and identified eight novel polymorphisms in CYSLTR2 by direct sequencing. A transmission disequilibrium test with 137 Japanese asthmatic families revealed that the -1220A > C polymorphism is associated with the development of asthma (P = 0.0066). In addition, a polymorphism in the putative promoter region caused different promoter activities in vitro.

CONCLUSION

Our results suggest that CYSLTR2 is one of the genes that contributes to susceptibility to asthma in the Japanese population.

Influences in allergy: epidemiology and the environment

Many decades after the first descriptions of hay fever in the 19th century, we still struggle with the formation of a cogent conception embracing all the many fragments of insight into the various aspects of allergic and asthmatic diseases. Although in daily practice we can grasp and allocate most of the clinical manifestations, in research the fundamental structures are only in part recognized. We therefore presume that the underlying mechanisms are complex and multifaceted. We have explored in countless directions while branching into ever more detailed analyses of phenomena, all of which are associated with the conditions of interest. But how can we rearrange these pieces to advance toward a broader understanding of asthma and allergies? Epidemiology as a scientific tool to study the occurrence, the natural course, and the determinants of a condition in various sociocultural environments might contribute to the edifice of such a scaffold. This review does not intend to present a comprehensive digest of the relevant literature: the reader can refer to other "state of the art" reviews. The intention is to discuss some conceptual cornerstones and to illustrate them with a few examples.

Double-blind, placebo-controlled study of the efficacy and tolerability of nimesulide administered orally in acute bronchial asthma

In this double-blind, placebo-controlled study, children with acute exacerbation of bronchial asthma between the ages of 1 and 12 years not responding to conventional therapy with bronchodilators and injectable steroids were enrolled. A total of 60 children (two groups of 30 each) was studied. The overall response to therapy was assessed based on the guidelines and recommendations of the National Heart, Lung and Blood Institute. The efficacy parameters included respiratory and heart rates, degree of dyspnea, accessory muscle usage, color, wheeze, and degree of oxygen saturation. Children with moderate to severe exacerbation received either nimesulide suspension 1.5 mg/kg per dose or identical placebo orally as per random protocol. To assess the clinical progress, all the efficacy parameters were reassessed after 30 minutes and 1, 2, and 6 hours. A significant difference was observed in the overall assessment of response at 1, 2, and 6 hours in the two treatment groups. A greater number of children showed a good overall response in the nimesulide group compared with the placebo group at 1, 2, and 6 hours (P <.01). No side effects were reported in any of the patients in either group. None of the patients was withdrawn prematurely from either group. It is evident from the current study that nimesulide showed good efficacy and tolerability. Therefore, nimesulide could be administered to asthmatic patients whenever there is a need for such therapy.

Familial risk of asthma among adolescents and their relatives in Taiwan

Although family studies have established that asthma has a hereditary basis, little evidence has been presented about the family risk of simple asthma (AS or nonatopic asthma) and asthma with other atopic diseases (AWAD or atopic asthma) after adjusting for potential risk factors. In this study, data were collected on demographic variables and a wide range of known risk factors for asthma. Study participants were asthmatic adolescents and controls, and their relatives. The role of a familial history of asthma and atopic diseases in predicting asthma risk among asthmatic adolescents and their relatives was evaluated in a population-based family study conducted in southern Taiwan. Asthma risk factor data were collected through telephone interviews with students' parents for 207 asthmatic adolescents 11-16 years of age, their 1600 relatives, and 207 nonasthmatic adolescents in the control group and their 1638 relatives. The results show (after adjusting potential confounders) that a family history of asthma is highly associated with asthma in adolescents. Having two or more family members with asthma was associated with a 3.4-fold (95% confidence interval [CI] = 1.0-12.0) increased risk of asthma among adolescents. Logistic regression was used to assess the effects of having an asthmatic relative and the effect of atopic diseases among relatives of cases. Having a family history of asthma and other atopic conditions, such as rhinitis and atopic dermatitis (adjusted odds ratio [AOR] = 3.64, 95% CI = 2.29-5.74 and AOR = 1.94, 95% CI = 1.53-2.46, respectively), was found to be a significant predictor of asthma in children. Along with a history of allergic rhinitis or atopic dermatitis, familial risks of asthma occurring in adolescents with and without other atopic diseases will be analyzed separately. A critical finding was the significant difference in a risk of asthma and atopic diseases among the relatives of asthma cases with atopic diseases and controls. However, for relatives of asthma cases without atopic diseases compared to control probands, AORs were highly significant for family history of asthma, but not for the family history of atopic diseases. These findings suggest that both forms of asthma may be hereditary, but there are differences in their modes of inheritance. Atopic status itself did not predispose a child to AS. A concomitant inheritance of a predisposition to asthma and atopic condition for AWAD cases was suggested.

Familial related risk-factors in the development of chronic bronchitis/emphysema as compared to asthma assessed in a postal survey

There is a lack of knowledge to which extent heredity or familial risk factors are involved in the development of chronic bronchitis/emphysema (CBE). Smoking is regarded as the most important risk factor, but only about 15% of smokers develop airway obstruction. We evaluated the importance of familial risk factors compared to smoking and ex-smoking using an epidemiological approach. In 1992, a postal questionnaire was distributed to a study sample. In all, 43 questions were asked, in a previously evaluated questionnaire, regarding respiratory symptoms, self-reported lung diseases, smoking habits and familial occurrence of chronic bronchitis and asthma. The questionnaire was sent to 12,073 adults living in the southernmost part of Sweden. The age range was 20-59 years with an equal gender distribution. The study sample was drawn from the population records. The questionnaire was answered by 8469 subjects (70.1%), of whom 392 subjects (4.6%) stated that they had or had had CBE and 469 subjects (5.5%) stated that they had or had had asthma. In a model with logistic regression using the five explanatory variables gender, age, familial occurrence for asthma, familial occurrence for CBE and current or ex-smoking the most important risk factors for CBE were familial occurrence for chronic bronchitis [Odds ratios (OR): 5.19, 95% confidence interval (CI): 4.09-6.60, p = 0.000] and current or ex-smoking (OR: 1.74, 95% CI: 1.41-2.14, p = 0.000). The most important risk factors for asthma were familial occurrence for asthma (OR: 3.71, 95% CI: 3.06-4.51, p = 0.000) and current or ex-smoking (OR: 1.33, 95% CI: 1.09-1.61, p = 0.004). We have found that familial occurrence for CBE in first degree relatives together with smoking is a stronger risk factor for the development of CBE than is smoking.

Mutation screening of interferon regulatory factor 1 gene (IRF-1) as a candidate gene for atopy/asthma

BACKGROUND

IL-4 gene cluster on chromosome 5 contains several candidate genes for atopy and asthma. Several independent studies have shown evidence for linkage between the markers flanking IL-4 gene cluster and asthma and/or asthma-related traits. Interferon regulatory factor 1 (IRF-1) is located approximately 300 kb telomeric to IL-4 and recent study reveals that IRF-1 deficiency results in an elevated production of Th2-related cytokines and a compensatory decrease in the expression of native cell- and Th1-related cytokines.

OBJECTIVE

To determine if there are any mutations associated with the development of atopy and asthma present in the coding exons and 5' flanking region of the IRF-1 gene.

METHODS AND RESULTS

We have screened the promoter and coding regions of the IRF-1 gene in atopic asthmatics and controls by SSCP method. We found three novel nuclear variants (the -300G/T and 4396 A/G polymorphisms and the 6355G > A rare variant) in the IRF-1 gene. No variants causing amino acid alterations of IRF-1 were detected. The -300G/T polymorphism was in nearly complete linkage disequilibrium with the 4396 A/G polymorphism. An association between the 4396 A > G polymorphism and atopy/asthma was examined by transmission disequilibrium test in 81 asthmatic families. Either of 4396 A or 4396G alleles was not significantly preferentially transmitted to atopy- or asthma-affected children.

CONCLUSION

The IRF-1 gene is less likely to play a substantial role in the development of atopy and asthma in the Japanese population.

Genomic approaches to understanding asthma

Asthma is the most common chronic childhood disease in developed nations, and it is a complex disease that has high social and economic costs. Asthma and its associated intermediate phenotypes are under a substantial degree of genetic control. The genetic aetiology of asthma offers a means of better understanding its pathogenesis and, thus, improving preventive strategies, diagnostic tools, and therapies. Considerable effort and expense have been expended in attempts to detect genetic loci contributing to asthma susceptibility, and extensive candidate gene studies and a number of whole-genome screens have been undertaken. This article reviews the current state of knowledge of the genetics of asthma, with a focus on genomic approaches to understanding allergic diseases.

Regressive logistic modeling of familial aggregation for asthma in 7,394 population-based nuclear families

The aim of this population-based study was to determine whether asthma aggregates in families, and if so, whether aggregation was consistent with environmental and/or genetic etiologies. Data were from 7,394 nuclear families (41,506 individuals) from the 1968 Tasmanian Asthma Survey, in which all Tasmanian schoolchildren born in 1961 were surveyed by respiratory questionnaire completed by their parents. Similar data were obtained for parents and siblings of probands. For a child, having ever had asthma was predicted by a parent or sibling having ever had asthma; odds ratio (OR) = 3.13 (95% confidence interval [CI] 2.82-3.48) for mother, 2.99 (2.69-3.32) for father, and 3.47 (3.23-3.72) for a sibling. Regressive logistic modeling showed that, in addition to parent-offspring effects, the data were consistent with the existence of an unmeasured factor shared by siblings, evident in 15% (SE 2%) of families and associated with a conditional OR of 9.68 (8.27-11.32). Familial aggregation was best described by a general oligogenic model with non-Mendelian transmission probabilities. Of the Mendelian models, a codominant model with an allele frequency of 16% (SE 0.3%) was preferred. Under a dominant model there was evidence for additional parent-offspring and sibling effects of similar magnitude. It is unlikely that there is one major loci influencing asthma susceptibility; the overall effects of asthma genes in the population are more likely to be inherited codominantly, at least for the majority of loci of major etiological importance. The role of environmental factors in explaining part of familial aggregation for asthma cannot be ruled out, as major triggers of asthma attacks are familial.

Risk factors for early, persistent, and late-onset wheezing in young children. SIDRIA Collaborative Group

Wheezing in childhood is not a single disorder and different wheezing-associated respiratory illnesses have been recently described. We investigated the association between wheezing conditions and familial, pre-, peri-, and postnatal risk factors. We studied 16,333 children, 6 to 7 yr old, enrolled in a population-based study. Standardized questionnaires were filled in by parents. A total of 1,221 children had transient early wheezing, 671 had persistent wheezing, 918 had late-onset wheezing, and 13,523 never had wheezing or asthma (control group). Maternal asthma or chronic obstructive airway disease were significantly (p < 0.0001) more associated with persistent wheezing than with transient early and late-onset wheezing. The same pattern was observed for exposure to maternal smoke during pregnancy. Having a mother > 35 yr old was protective against transient early wheezing (odds ratio [OR]: 0.68, 95% confidence intervals [95% CI]: 0.53 to 0.86). Breast feeding >/= 6 mo was slightly protective against transient early wheezing (OR: 0.82, 95% CI: 0.68 to 0.97), whereas it was a moderate risk factor for late-onset wheezing (OR: 1.22, 95% CI: 0.99 to 1.50). On the contrary, having siblings and attending a day care center were both risk factors for transient early wheezing (OR: 1.41 [95% CI: 1.21 to 1.64] and 1.70 [95% CI: 1.48 to 1.96], respectively) and protective factors against wheezing of late onset (OR: 0.83 [95% CI: 0.70 to 0.97] and 0.72 [95% CI: 0.59 to 0.88]). There was a stronger (p < 0.0001) positive association between personal history of eczema or allergic rhinitis and persistent and late-onset wheezing than transient early wheezing. Our findings suggest a different contribution of risk factors to wheezing conditions in childhood.

Linkage and association of atopic asthma to markers on chromosome 13 in the Japanese population

Chromosome 13 contains several candidate genes for asthma and atopy, and markers on this chromosome have been shown to be linked to phenotypes of atopy or asthma in two genome-wide searches. We conducted a linkage study for atopic asthma using markers spanning the whole of chromosome 13 in Japanese families ascertained through asthmatic children and examined associations of atopic asthma with markers where linkage was suggested. Data were analysed using MAPMAKER/SIBS for the multipoint lod score (MLS) analysis and SIB-PAIR for the transmission dis-equilibrium test (TDT). Three peaks which exceeded a lod score of 1.0 were observed (MLS 2.4 between D13S175 and D13S217, MLS 2.0 between D13S153 and D13S156, and MLS 1.4 between D13S285 and D13S293). The global TDT for atopic asthma was significant for the marker D13S153 ( P = 0.0065) and the 96 bp allele of D13S153 was preferentially transmitted to atopic asthma-affected children ( P = 0.0009, Bonferroni correction 5% = 0. 0037, 1% = 0.00072). These findings indicate that genes on chromosome 13 may play an important role in the development of atopy or asthma across various populations.

Effect of dietary vitamin E supplementation on murine nasal allergy

BACKGROUND

Although many studies have reported the effects of dietary vitamin E on the immune response, none so far has assessed its role in nasal allergy.

METHODS

Female BALB/c mice were randomized into two groups and fed a 20% casein diet (control group, 50 mg vitamin E/kg diet) or this diet supplemented with 535 mg vitamin E/kg diet (vitamin E group, 585 mg vitamin E/kg diet) for 4 weeks. During the fifth week, the mice in each group were divided into two subgroups to form a total of four treatment groups: group A (control), group B [control + toluene diisocyanate (TDI) sensitization], group C (vitamin E supplementation), and group D (vitamin E supplementation + TDI sensitization). Groups B and D were treated with two courses of intranasal application of 5% TDI in ethyl acetate, whereas groups A and C were treated with ethyl acetate alone. A week after second sensitization all groups were provoked by applying 2.5% of TDI in the vehicle and nasal allergic responses were observed for 10 minutes. Splenic lymphoproliferation, splenic cell cytokines, and the total serum IgE were measured.

RESULTS

Members of group D had lower (P < 0.01) scores of nasal response and sneezed less frequently (P < 0.01) than those of group B. Similarly, splenic lymphoproliferation and production of IL-4 and IL-5 as well as the total serum IgE levels were lower (P < 0.01) in group D than in group B.

CONCLUSIONS

The results indicate that higher doses of vitamin E supplementation may suppress nasal allergic responses.

No association between atopy/asthma and the ILe50Val polymorphism of IL-4 receptor

Susceptibility to atopic diseases is known to involve genetic factors. The interleukin-4 (IL-4) receptor- alpha gene (IL4R) reportedly is involved in the development of atopy. A recent study has shown the Ile50 allele of a polymorphism (Ile50Val) of IL4R to be associated with atopy. The objective of this study was to replicate this association and confirm the possible role of the Ile50Val polymorphism of IL4R in the etiology of atopic asthma in a Japanese population. We conducted a transmission disequilibrium test in 86 families identified through asthmatic children. A case-control study was also carried out using both atopic and control subjects. The IL4R Ile50Val polymorphism was genotyped by a PCR-restriction fragment length polymorphism method using an intronic upstream primer. The IL4R Ile50 allele was not preferentially transmitted to atopy- or to asthma-affected children. Neither the Ile50 allele nor the Ile50/Ile50 genotype was more prevalent in the atopic subjects than in the control subjects. Our findings indicate that the Ile50Val polymorphism of IL4R does not play a substantial role in genetic predisposition for the etiology of atopy or asthma in this Japanese population.

Lack of association of atopy/asthma and the interleukin-4 receptor alpha gene in Japanese

BACKGROUND

Susceptibility to the development of atopic diseases is known to involve genetic factors. Several investigators have reported the interleukin-4 (IL-4) receptor alpha gene to be involved in the development of atopy. Recent study has shown that the R allele of a polymorphism in the IL-4 receptor alpha chain gene (Q576R) to be associated with atopy.

OBJECTIVE

The objective of this study was to evaluate the possible role of the IL-4 receptor alpha gene in modulating allergic response and asthma in the Japanese population.

METHODS

We conducted linkage analysis using microsatellite markers flanking the IL-4 alpha receptor gene in 82 families ascertained through asthmatic children. The IL-4 receptor Q576R polymorphism was also genotyped by PCR-restriction fragment length polymorphism analysis.

RESULTS

We did not find evidence for linkage of the asthma and atopy phenotypes with the markers D16S298 and D16S403 (P = 0.10 and P = 0.56, respectively, for the atopy phenotype and P = 0.17 and P = 0.60, respectively, for the asthma phenotype). The IL-4 receptor R576 allele was not preferentially transmitted to atopy- or asthma-affected children (chi2 = 1.67, P = 0.24 for atopy and chi2 = 0.91, P = 0.40 for asthma). In addition, the prevalence of the R576 allele among parents with and without atopy was similar, 20 of 81 (24.7%) parents with atopy and 22 of 77 (28.6%) parents without atopy.

CONCLUSION

Our findings indicate that the IL-4 receptor alpha gene does not exert a substantial influence on the inheritance of atopy or asthma in this Japanese population.

Prevalence of specific allergic diseases in school children as related to parental atopy

BACKGROUND

Our objective was to investigate the influence of parental allergy on the manifestations and course of allergic disease in children.

METHODS AND RESULTS

A total of 15,234 school children aged 6 and 9 years were evaluated by means of questionnaires completed by their parents in a cross-sectional survey conducted in Tokushima, Japan. The prevalence and relative risk ratio (RRR) for parental allergy in children with atopic dermatitis, asthma and allergic rhinitis were 6.4% (RRR 2.5), 3.2% (RRR 2.4) and 15% (RRR 2.4), respectively. The risk of atopic dermatitis was particularly high in children whose parent had atopic dermatitis, with an RRR of 2.8 (father) and 3.7 (mother). Children with a parental history of asthma also had a high risk of that disorder (RRR of father 5.3, mother 6.2). However, the risk of allergic rhinitis was no different in children with a parental history of allergic rhinitis or from children with a parental history of asthma and atopic dermatitis. A history of allergic disease in both parents, especially of asthma and atopic dermatitis, increased the risk of allergic disease in the child. Milder symptoms, such as wheezy bronchitis, in schoolchildren were similarly related with the same hereditary tendency as the identical allergic disease. The disappearance of allergic symptoms with age also related to a hereditary component, being less likely in children with a history of parental allergy than in those without such an atopic history.

CONCLUSIONS

The manifestations and course of allergic disease in school children relate to parental allergic disease.

Verification of self-reported asthma and allergy in subjects and their family members volunteering for gene mapping studies

Studies which aim at mapping genes contributing to the development of asthma and atopy demand that hundreds of patients and their family members be assessed. In Finland, the Social Insurance Institution (SII) grants substantial reimbursement for medication to all patients who meet diagnostic criteria of asthma, which include a history of asthmatic symptoms and a measured reversibility of bronchial obstruction. To recruit a large number of asthma patients efficiently in a short period of time, we took advantage of the national reimbursement procedure and retrospectively collective data on patients' medical history and lung function test results at the time of diagnosis. First, we wanted to investigate if the reimbursements could be regarded as objective verification for self-reported asthma. Altogether 335 adult self-reported asthma patients were evaluated, 87% of them were verified as having chronic asthma. Reimbursement for medication showed a sensitivity of 95% and a specificity of 76% for verified asthma. Second, we were interested to see if self-reported nasal allergic symptoms or self-reported physician diagnosed allergic rhinitis were sensitive and specific measures of allergy. The self-reported allergic nasal symptoms had a poor specificity (31% in the proband group and 59% in the family members group) when compared to the allergy screening test (Phadiatop). The best verification for self-reported asthma was achieved by combining the information on self-reported disease, granted reimbursement by the SII and the medical records. For allergies, the specificity of self-reporting was far too low to be used alone, and a positive allergy screening test together with relevant symptoms was chosen as a marker of allergy.

Mapping susceptibility genes for asthma and allergy

Using family data, linkage analysis has been performed to determine the location in the genome of susceptibility genes for allergy and asthma. It has now become clear that there are multiple regions of the genome that contain susceptibility genes for allergy and asthma. The results from two genome screen studies will be reviewed and compared with results from candidate gene approaches. Results from several studies show evidence for linkage to chromosomes 5, 6, 11, 12, 13 and 14 for atopy, asthma or a related phenotype such as total serum IgE levels. Many of these regions contain candidate genes involved in regulating processes that may be involved in the development or progression of allergy and asthma. Some susceptibility genes may affect the expression of these disorders while others may affect response to therapy. Susceptibility to developing allergy or asthma appears to be due to the interaction of multiple genes with the environment.

Prevalence of bronchial asthma in schoolchildren in Delhi

There is a paucity of information on the prevalence of asthma in children in India. Some evidence suggests that asthma is less common in developing than in the developed countries. The present study was carried out to estimate its current magnitude in children in Delhi. The questionnaire-based study was carried out in two randomly selected schools in Delhi. All the children were eligible. The age range was 4-17 years. The questionnaires were distributed to all the children present (n = 2867) to be answered by either parent. The key questions were related to complaints of recurrent wheezing in the past, in the last 1 year, and also wheezing exclusively induced by exercise or colds. In all, 2609 questionnaires were completed and returned (response rate 91%). There was a slight excess of males (54%). The prevalence of current asthma was 11.6% and past asthma was reported by 4.1% of children, giving a cumulative prevalence of 15.7%. Exclusive exercise-induced asthma was 2.8% and that associated with colds, 2.3%. The current prevalence of all wheezing was thus 16.7% and cumulative prevalence was 20.8%. While there was no sex-related difference in prevalence, wheezers were the highest in the 9-13 year age group. A significant association was found between the prevalence of wheezing and a family history of asthma (odds ratio 3.65) and presence of smokers in the family (odds ratio 1.62). When both the above factors combined, the odds ratio for risk of asthma was 4.58. There was no significant association with any economic class. Only 11% of asthmatics had been labeled so by their physicians. The prevalence of bronchial asthma and wheezing in children in Delhi is quite high and comparable to that reported from several developed countries. A positive family history of asthma and presence of smokers in the family emerged as significant risk factors.

Characterization of obstructive airway disease in family members of probands with asthma. An algorithm for the diagnosis of asthma

To investigate the genetic susceptibility to asthma, we developed an algorithm to classify the phenotype of each family member enrolled in a family study on the genetics of asthma. This algorithm was applied to 92, two- and three-generation families, identified through a subject (proband) with asthma first diagnosed 25 yr previously. The algorithm consisted of five classes based on the presence or absence of bronchial hyperresponsiveness (BHR), respiratory symptoms, smoking, airways obstruction, and bronchodilator reversibility. All family members were classified as: (1) definite asthma; (2) probable asthma; (3) unclassifiable airway disease; (4) chronic obstructive pulmonary disease (COPD); (5) unaffected (without clinical evidence of asthma and COPD). Thirteen of the 92 probands (14%) could not be classified as asthmatic when retested 25 yr later because of loss of BHR, loss of bronchodilator reversibility, or a current history of cigarette smoking. Of the 265 first-degree offspring, 49 (18%) were classified as having definite asthma (Class 1), and 22 (8%) as probable asthma (Class 2). A large number of offspring with clinical evidence of asthma did not have a prior physician's diagnosis of asthma, and offspring in Class 1 (definite asthma), with and without a physician's diagnosis, had similar clinical and physiologic characteristics. These results support the usefulness of this approach to classify subjects with asthma for genetic epidemiologic studies and show that reliance on a prior physician's diagnosis may result in misclassification or underdiagnosis. Characterization of the offspring in this family study showed that there is familial clustering, which supports the presence of a hereditary component in asthma.

Association of asthma and the interleukin-4 promoter gene in Japanese

BACKGROUND

Susceptibility to the development of asthma and other atopic diseases is known to be associated with genetic components. Several investigator have linked the interleukin-4 (IL-4) gene and nearby markers located on chromosome 5 to atopy and asthma. Recent study has demonstrated that the T allele of a polymorphism in the IL-4 gene promoter region (C-590T) is associated with elevated levels of total serum IgE.

OBJECTIVE

The objective of this study was to evaluate the possible role of this IL-4 polymorphism (C-590T) in modulating the allergic response and asthma in Japanese children.

METHODS AND RESULTS

The study was conducted in two different populations: families ascertained through asthmatic children (asthmatic group, 306 members) in whom linkage of asthma and atopy to chromosome 5q31-33 is suggested and a random general population (control group, 215 members). The IL-4 C-590T polymorphism was genotyped by PCR-restriction fragment length polymorphism analysis. Frequency of the T allele was 0.73 in the asthmatic group and 0.70 in the control group. No significant difference in the levels of total serum IgE and specific IgE to house dust mite was observed between subjects with homozygote for the C allele, a heterozygote and a homozygote for the T allele by intrafamilial and interfamilial comparisons. Using the transmission disequilibrium test, however, we found a significantly frequent transmission of the T allele to asthmatic children (chi2=5.72, P=0.023).

CONCLUSION

Our data suggest that the IL-4 promoter C-590T polymorphism may be associated with the development of asthma in Japanese children, but not through modulating total serum IgE levels.

Analytic options for asthma genetics

The analytic methods currently being used for the study of the genetics of asthma have primarily focused on the evaluation of linkage by non-parametric methods as applied to genome screen data in affected sibling pairs. Complexity in the analysis of asthma genetics has been shown to occur at several levels, including phenotypic definition (wide vs narrow criteria for asthma, including restriction based upon multiple phenotypes) and joint analysis of asthma with associated phenotypes. Alternative approaches that purport to treat asthma as a quantitative trait (a 'score' or 'index') rather than as a qualitative (asthma, yes or no) trait were presented, including the development of a 'Framingham Risk Score' for asthma, a selection index, or a propensity score. While each of these alternatives have interesting features, issues relating to estimation and incorporation in a family structure have yet to be resolved. Nonetheless, collection of a standard set of clinical data from multiple studies could be used in a score to increase the power of genetic mapping studies for asthma.

Outcome of children of parents with atopic asthma and transient childhood wheezy bronchitis

BACKGROUND

Childhood asthma and wheeze only in the presence of respiratory infection (wheezy bronchitis) appear to have different prognoses and may differ in their aetiology and heritability. In particular, slight reductions in lung function may be associated with episodes of wheezing associated with intercurrent viral infection.

METHODS

Outcomes for wheezing symptoms and lung function were studied in 133 offspring of three distinct groups of 69 middle aged probands with childhood histories of (1) atopic asthma (n = 18), (2) wheeze associated with upper respiratory tract infection (wheezy bronchitis, n = 24), and (3) no symptoms (n = 27). Probands were selected from a previously studied cohort in which outcomes of wheezy bronchitis and asthma had been shown to differ.

RESULTS

Children of probands with wheezy bronchitis had a lower prevalence of current wheezing symptoms. Forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) in boys of probands with a history of wheezy bronchitis were significantly reduced compared with either of the other two groups (p < 0.0001). In a multivariate analysis, grouping based on parent proband had a significant effect on lung function, independent of factors such as symptoms, atopy or smoking history.

CONCLUSIONS

The different symptomatic and lung function outcome in children of probands with wheezy bronchitis and asthma provides further evidence that wheezy bronchitis and asthma differ in their natural history and heritability, and suggests that there may be familial factors specific to each wheezing syndrome.

Evidence for linkage between asthma/atopy in childhood and chromosome 5q31-q33 in a Japanese population

Susceptibility to the development of asthma and other atopic diseases is known to be associated with genetic components, and several candidate genes have been reported to be linked to atopy in Caucasian populations. We conducted a study of linkage between asthma and markers on chromosomes 5q31-q33 and 11q13 in 68 Japanese families (306 members) by affected sib-pair analysis. Families for the linkage study were ascertained through asthmatic children visiting the allergy clinic. The results provide supportive evidence for linkage between asthma and gene markers in or near the interleukin-4 (IL-4) gene, the IL-9 gene, and D5S393 on chromosome 5q31-q33 (p = 0.0013, p = 0.018, and p = 0.0077, respectively). Linkage between atopic phenotype and these genetic markers was also suggested (p = 0.006, p = 0.01, and p < 0.0001 for atopy, respectively). However, we failed to find evidence for linkage of asthma or atopy to the IgE high-affinity receptor gene on 11q13 (p > 0.1). These findings indicate that beyond ethnicity, there are specific loci that contribute to susceptibility to atopy on chromosome 5q31-q33. In addition, our findings suggest that loci on chromosome 5q31-q33 are linked to the development of asthma in childhood.

Progression of allergy and asthma through childhood to adolescence

The reduction in asthma symptoms and bronchial hyperresponsiveness in adolescence is not well understood. Nor can the differences in asthma prevalence and severity between the sexes, which reverse at puberty, be explained. It has been suggested that the improvement in asthma during adolescence may result from diminished clinical and immunological responsiveness directly related to hormonal changes and that the effect of age on the prevalence of asthma in each sex may relate to differences in hormonal status, potentially influencing airway size, inflammation, and smooth muscle and vascular functions. However, few comprehensive studies are available. In summary, all wheezing is not asthma. Non-asthmatic wheezing illnesses may in part be attributable to anatomical abnormalities of the lung (transient early wheezing, premature birth). Little is known about the genetic and environmental determinants of childhood asthma, and factors related to the development of atopic sensitisation, such as exposure to allergens, infectious diseases, or tobacco smoke early in life, and dietary habits may be important, whereas the relevance of air pollution remains to be established. Unfortunately, we still do not know how to prevent the manifestation of childhood asthma.

Risk factors for asthmatic patients requiring intubation. I. Observations in children

There are significant concerns regarding the increased mortality of patients with asthma. Indeed the paradox of improved pharmacotherapy but worsening prognosis has been explored in depth in several studies including observations in epidemiology, access to medical care, and drug toxicity. Because of our ability to track all admissions to a tertiary-care hospital, we attempted to define the demographic data from a population of asthmatic children admitted for asthma in order to identify risk factors for intubation. We performed a retrospective cohort study of all asthma admissions excluding patients with cystic fibrosis. This study included all asthmatics aged 5-12 years admitted over a 10-year period (1984-1994) to the University of California at Davis Medical Center, Sacramento. A total of 300 such asthma admissions were reviewed, involving 135 girls and 165 boys, mean age 7.7 +/- 2.4 years. Of this group, 166 children were black, 70 were Caucasian, 49 were Hispanic, 14 were Asian, and 1 was an American Indian. By National Heart, Lung, and Blood Institute guidelines, this group included 147 mild, 117 moderate, and 36 severe cases. Thirteen children required intubation for their asthma. Significant risk factors identified for children requiring intubation, compared to those who did not require intubation, were secondhand smoke exposure [odds ratio (O.R.) 22.4; 95% confidence interval (C.I.) 7.4, 68.0], psychosocial problems (O.R. 13.5; 95% C.I. 5.1, 36.0), family dysfunction (O.R. 13.0; 95% C.I. 3.9, 43.9), upper respiratory infection (O.R. 10.2; 95% C.I. 3.4, 28.1), little formal education (O.R. 8.7; 95% C.I. 2.4, 31.6), prior asthma emergency room visit in past year (O.R. 7.2; 95% C.I. 1.9, 27.1), prior asthma hospitalization in past year (O.R. 7.1; 95% C.I. 2.2, 22.2), crowding (O.R. 6.9; 95% C.I. 2.5, 19.1), low socioeconomic status (O.R. 6.5; 95% C.I. 2.1, 20.8), steroid-dependent (O.R. 3.8; 95% C.I. 1.2, 12.1), parental history of allergy or asthma (O.R. 3.4; 95% C.I. 1.1, 10.0), and language barrier (O.R. 3.3; 95% C.I. 1.1, 10.6). Nonsignificant mild risk factors included inhaled cromolyn (O.R. 2.7; 95% C.I. 0.7, 10.0), atopy (O.R. 1.9; 95% C.I. 0.6, 5.9), and prior intubation (O.R. 1.6; 95% C.I. 0.2, 13.1). These risk parameters may be important determinants of baseline risk for asthma deaths and their recognition may have a significant impact on preventive measures.

Risk factors for asthmatic patients requiring intubation. II. Observations in teenagers

The asthma mortality rate has increased steadily over the past 15 years in the United States and has only recently shown signs of leveling off. It is widely believed, although unproven, that many asthma deaths may be preventable. We have addressed one critical factor in severe asthma by attempting a definition of risk factors for intubation using demographic data and a retrospective cohort study of hospitalized asthmatic teenagers. This study included all asthmatics aged 13-19 years admitted over a 10-year period (1984-1994) to the University of California Davis Medical Center, Sacramento, California. A total of 143 such asthma admissions were reviewed, involving 68 females and 75 males, mean age 16.4 +/- 2.3 years. Of this group, 85 teenagers were black, 34 were Caucasian, 14 were Hispanic, and 10 were Asian. By National Heart, Lung, and Blood Institute guidelines, there were 42 mild, 85 moderate, and 16 severe cases. Ten of the 143 teenagers studied required intubation for their asthma.(ABSTRACT TRUNCATED AT 250 WORDS)

Pet ownership in the UAE: its effect on allergy and respiratory symptoms

The aim of this paper was to study the effect of pets and other domestic animals on bronchial asthma among United Arab Emirates (UAE) schoolchildren aged 6-14 years. A cross-sectional study of 850 schoolchildren living in both urban and rural areas (average age 9.36 +/- 2.11 years, 46.8% boys and 53.2% girls) was conducted using self-administered questionnaires between October 1992 and May 1993. Prevalence rate for asthma, rhinitis, wheeze, cough, and eczema in children from families with and without animals were investigated. A total of 40.7% of families studied were found to keep animals in their homes. Children from families with animals were found to have a significantly higher prevalence rate of respiratory symptoms than those without. The prevalence rate for asthma in children with animals was found to be twice that of children without (RR: 2.03; 95% CI: 1.40-2.95). The risk of having chronic cough (RR: 1.93; 95% CI: 1.21-3.10), breathlessness/chest tightness (RR: 2.53; 95% CI: 1.59-4.02), chronic wheeze (RR: 2.10; 95% CI: 1.20-3.67), allergic rhinitis (RR: 1.53; 95% CI: 1.17-2.00) was significantly higher in children with animals than in children without. Similarly, the risk of having eczema (RR: 2.55; 95%, CI: 1.74-3.75) was significantly higher among children with animals than among those without. Overall, there was a highly statistically significant difference in the prevalence of asthma, wheeze, nocturnal cough, eczema, and rhinitis between children in families with animals and those without (p < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Psychophysiologic reactivity in asthmatic children: a cholinergically mediated confluence of pathways

OBJECTIVE

The purpose of this study was to determine the suitability of a newly developed experimental paradigm, designed to assess relationships among emotional responsivity, physiologic (autonomic) reactivity, airway reactivity, and pulmonary function in asthmatic children under controlled conditions of ecologically valid emotional stimulation.

METHOD

Twenty-four children, aged 8 through 17, with moderate to severe asthma viewed the movie, E.T., the Extra-Terrestrial, while having their heart and respiration rate and oxygen saturation continuously measured and recorded. Airway reactivity was assessed by the methacholine challenge test, and pre- and postmovie pulmonary function by spirometry. Self-report of emotion was recorded for targeted scenes.

RESULTS

Findings indicated that emotional responsivity and physiologic reactivity to the movie were associated with increased airway reactivity and with decreased pulmonary function.

CONCLUSIONS

The pattern of results suggests cholinergically mediated psychophysiologic pathways of emotional influence in the asthmatic process for some asthmatic children. A heuristic biopsychosocial model of these pathways is presented.

Association of allergic symptoms in children with those in their parents

This study investigated the association of asthma, allergic rhinitis, and eczema in United Arab Emirates (UAE) schoolchildren with allergic conditions in their parents. A cross-sectional, population-based study among schoolchildren aged 6-14 years was conducted in Al-Ain City, UAE. The field survey was conducted from October 1992 to May 1993. A questionnaire was distributed to 850 UAE government school students from representative, randomly selected schools with a majority of UAE nationals. The student and both or either of the parents were present during the interview. A detailed clinical history of asthma and wheezing in the target children and a history of asthma and allergic rhinitis in their parents and siblings were obtained. It was found that 13.1% of asthmatic children had mothers with asthma (relative risk (RR) = 2.67; 95% confidence intervals (CI) = 1.65-4.35), and 15.2% had fathers who were asthmatic (RR = 2.85; 95% CI = 1.81-4.49). This contrasted with 4.4% of nonasthmatic children who had fathers with asthma, and 4.1% who had mothers with asthma. A similar pattern was seen with symptoms of allergic rhinitis when it was found that 34.3% of children who had asthma had mothers with allergic rhinitis (RR: 2.74; 95% CI: 1.90-3.94). The corresponding figure for fathers was 12.7% (RR: 0.92; 95% CI: 0.5-1.7). The frequency of either parent of the asthmatic children having allergic rhinitis was 28.6%; for both parents, it was 14.5%. It was also found that asthmatic children had 12.5% of their fathers, 32.8% of their mothers, 26.4% of either of their parents, and 33.3% of both their parents suffering from allergic rhinitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Childhood asthma: diagnosis and treatment

This discussion of asthma management should be regarded as providing guidelines, not dogma. The underlying principles of asthma management include recognition of the variability of the disease and the importance of the underlying inflammatory condition. Clinical assessment is not enough and objective monitoring with PEFR or spirometry provides important data. The treatment protocols require individualization. It is important that the patient and family are team members working together with the medical staff toward a goal of good asthma management. In the discussion of the management of asthma, much emphasis was placed on spirometry and home measurement of PEFR. Office use of spirometry is now the norm for asthma management. Providing asthmatic patients with peak flow meters and instructions in their use is part of the routine care of asthma. Instruction of the patient and family in the proper use of medications is paramount. The MDI devices need to be prescribed with careful instructions regarding their use. When the patient comes in for follow-up, part of the examination should include the patient's demonstration of how he uses this device. Discussion of the proper and safe use of bronchodilators is important. Overuse of inhaled bronchodilators may be a reflection of increasing asthma or, at the very least, evidence that the patient does not understand appropriate treatment of asthma. If a patient is dependent on regular use of an inhaled beta agent, it is likely that he would benefit from therapy directed at the underlying inflammation of asthma. The patient and the family should understand the purpose of each medication, the side effects, and the risks and benefits of their use. In particular, if steroid medications are necessary, the reasons for their use should be explained. Carefully matching the severity of the asthma with the therapeutic protocols provides an organized approach to asthma treatment. Avoiding triggers of asthma and controlling the environmental exposure to potential triggers leads to lower medication requirements and less lability. Offering the family written instructions to cope with changes in the child's condition, based on assessment of clinical and PEFR observations, allows them more autonomy and comfort in the day-to-day care of the asthmatic child.

Respiratory conditions, including asthma, and height in primary school

The National Study of Health and Growth (NSHG) of primary school children has examined the relationships between height and each of six separate respiratory conditions, one of which was asthma, in children aged 5-11 years, allowing for a number of genetic and environmental confounding factors, in particular for parental height. The relationships were investigated in a 'representative' sample of 4974 Caucasian English children in 1984 and in an 'ethnic/inner city' sample of 3419 Afro-Caribbean/Indian and Pakistani/Caucasian English children in 1985. None of the respiratory conditions was found to be related to height except for 'wheeze most days', whether or not it was accompanied by an asthma attack in the last 12 months. The Caucasian children in the 'representative' sample who had 'wheeze most days', were 0.17 height standard deviation score (95% confidence interval 0.03 to 0.31) less (approximately 1 cm) than those with no wheeze. Comparisons with previous results for NSHG 'representative' Caucasian English children in 1973 showed good agreement except for children with three or more asthma attacks who were found to be shorter in 1973, but not in 1984, which may reflect improved treatment, or milder asthma being reported in 1984. It was concluded that, in the 1980s, the respiratory conditions were not related to height. The exception was 'wheeze most days'. It is suggested that this is an indicator of sickness, most likely asthma, which is being experienced with sufficient severity to affect growth slightly.

Heredity of asthma in Saudi population

In a cross-sectional study, the prevalence of asthma, hay fever and eczema was studied in 1150 schoolchildren attending school in Jeddah Western region of Saudi Arabia. The family histories of asthma, hay fever and eczema were examined in first degree relatives. The age range of children studied was 7-12 years, with a mean of 9.3 years (47% boys and 53% girls). A self-administered questionnaire was completed by the parents of the child to collect information concerning bronchial asthma, hay fever, and eczema in the target child and family history of respiratory allergy. A detailed family history and personal histories of asthma were available for 1035 Saudi children aged 7-12 years old. The rate of asthma and hay fever were significantly higher among siblings and offspring (cases) compared to their parents (p < 0.001). The results showed a high positive correlation between the relatives of affected children with respect to asthma and hay fever. These findings support the hypothesis that asthma and hay fever may be inherited in the Saudi population, but the mode of inheritance has yet to be determined.

Genetic risk for asthma, allergic rhinitis, and atopic dermatitis

In order to explore the genetic risk of a child with a family history of allergies developing asthma, allergic rhinitis, or atopic dermatitis, questionnaires filled in by 6665 families were analysed. The data were collected in a population based cross sectional survey of 9-11 year old schoolchildren living in Munich and southern Bavaria. The relation between asthma, allergic rhinitis, and atopic dermatitis and the number of allergic first degree relatives, and the type of allergic disease was examined. Analyses were done separately for families with single or multiple allergic diseases. In families with one allergic parent the risk of the child developing asthma was increased by asthma in a parent, with an odds ratio (OR) of 2.6 (95% confidence interval 1.7 to 4.0) but not by parental allergic rhinitis with OR 1.0 (0.7 to 1.5) or atopic dermatitis, OR 1.0 (0.6 to 1.6). For allergic rhinitis the highest risk with OR 3.6 (2.9 to 4.6) was observed with allergic rhinitis of one parent, apparently lower for asthma of one parent, OR 2.5 (1.6 to 4.0) or atopic dermatitis, OR 1.7 (1.1 to 2.5). Children with parental atopic dermatitis had a high risk for atopic dermatitis, OR 3.4 (2.6 to 4.4), compared with children with parental asthma, OR 1.5 (1.0 to 2.2), or parental allergic rhinitis, OR 1.4 (1.1 to 1.8). Risk factors in families with combined allergies of two relatives (parents and siblings) were analysed separately for the different combinations. These results support the hypothesis that asthma, allergic rhinitis, and atopic dermatitis are multifactorial diseases brought about by various familial and environmental influences.

Influence of a positive family history and associated allergic diseases on the natural course of asthma

The outcome of childhood asthma was studied in a cohort of 406 asthmatic children, with emphasis on the influence of family history for allergic disease, as well as the influence of associated allergic diseases on prognosis. Sixty-two per cent had a positive family history for atopy. In young adulthood no differences, either in symptoms or lung function were demonstrated in comparison to subjects with a negative family history. Fifty-two per cent of the children had no other allergic disease, 48% had either eczema or hay fever or both. When subjects were stratified based on associated allergic disease, no differences in outcome in adulthood were revealed either. It is concluded that neither a positive family history, nor concurrent associated allergic diseases in the child contribute to the prognosis of asthma from childhood to young adulthood. Therefore, environmental factors as well as patient characteristics (including lung function level, level of bronchial responsiveness) are likely to be more important for the prognosis.

Asthma and employment in young adults

BACKGROUND

Little is known about the effect of asthma on employment. The relation between employment history at the age of 23 years and a history of asthma or wheeze was investigated in a controlled prospective study using data collected in the National Child Development Study, a longitudinal survey of all children born in the United Kingdom in one week in March 1958.

METHODS

Information about subjects' medical condition was collected at four ages (7, 11, 16, and 23 years) for the original cohort of 17,319 births. At 23 years information about employment and education was obtained for 12,534 subjects (72%), of whom 460 (4%) had current asthma or wheeze, 2758 (22%) had past asthma or wheeze, and 5161 (41%) had never had asthma or wheeze. The remaining subjects could not be classified accurately.

RESULTS

The risk of unemployment was higher in subjects with a current history of asthma or wheeze (odds ratio 1.32, 95% confidence interval (CI) 1.09-1.61) or a past history of asthma or wheeze (odds ratio 1.54, 95% CI 1.27-1.85) than in those with no such history, after subjects' sex, region of birth, maximum educational qualification, and father's social class had been controlled for. Current and past asthma or wheezing illness predicted a worse employment history in terms of most of the outcomes examined, including mean percentage of months employed since leaving school, mean number of months in current full time job, mean percentage of months unemployed since leaving school, likelihood of being out of the labour force owing to long term illness, and the proportion attaining social groups 1-3. The differences from those who had never had asthma or a wheezing illness were, however, small and generally non-significant.

CONCLUSION

Asthma has only a small adverse effect on employment in young adults.

A population-based study of bronchial asthma in adult twin pairs

Aggregation of cases of bronchial asthma in adult twin pairs was studied in the nationwide Finnish twin cohort consisting of 13,888 adult monozygotic (MZ) and same-sex dizygotic (DZ) pairs. Cases of asthma were ascertained by record-linkage from three sources of data: death certificates from the Central Statistical Office; hospital discharges from the nationwide hospital registry; and the nationwide registry for fully reimbursed medications of the Social Insurance Institution. A diagnosis of bronchial asthma in one or more of these registers was obtained for 525 (236 men and 289 women) out of 27,776 twin individuals. Among MZ pairs, ten concordant and 138 discordant pairs were identified, while among DZ pairs, 12 concordant and 343 discordant pairs were found. In the whole sample the observed-expected ratio for the number of pairs concordant for bronchial asthma was 4.30 (95 percent confidence interval [CI], 2.06 to 7.90) in MZ pairs and 2.61 (95 percent CI, 1.35 to 4.56) in DZ pairs. Using a multifactorial threshold model, we estimated the correlation in liability to asthma as 0.425 (SE = 0.07) in MZ twins and 0.247 (SE = 0.06) in DZ twins, and we obtained a heritability estimate of 35.6 percent. The data also showed a gender difference in asthma heredity, which may, however, be due to chance events affecting the distribution of concordant pairs.

Early asthma onset: consideration of parenting issues

This report examines the relationship between early parental behavior and the later onset of asthma in a cohort of 150 children who were genetically at risk for developing asthma. Judgments of both parenting problems and maternal coping were made during a home visit when the infant was 3 weeks old. A clinical interview with the mother was developed and reliably coded. The sample was divided into two groups based on the presence or absence of concerns about coping and parenting. During the following 2 years, the respiratory status of the children was monitored. Four categories of respiratory status were defined: (1) asthma; (2) recurrent infectious wheezing; (3) a single isolated wheezing episode; or (4) no wheezing. Early problems in coping and parenting were associated with the later onset of asthma (p less than 0.001). Furthermore, parents of children who developed asthma were more likely to have been having difficulties at the 3-week visit than those whose children developed infectious wheezing (p less than 0.005).

The effect of symptom presentation on delay in asthma diagnosis in children in a general practice

Analysis of 187 children diagnosed as having asthma since 1984 in a general practice population is described. Reasons were sought for possible delay in diagnosis so that appropriate steps could subsequently be taken to minimize further delay. Even in an asthma aware practice (original prevalence 8.8%) a delay of approximately 40% of the total age of the child at diagnosis is shown. This delay does not appear to diminish even for children up to 10 years of age. Asthma is more likely to be missed or labelled as 'bronchitis' in children who cough repeatedly, rather than those who wheeze occasionally. As many as 45% of asthmatic children may have had 'bronchitis' diagnosed and treated instead of asthma, so that a diagnosis of repeated 'bronchitis' merely detracts from underlying asthma.