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PubMed2000

Absence of relationship between tuberculin reactivity and atopy in BCG vaccinated young adults.

BACKGROUND: An inverse association between tuberculin responses and atopy has been observed in Japanese children, indicating that BCG immunisation, subclinical exposure to Mycobacterium tuberculosis without clinical disease, or host characteristics may influence the T helper (Th) lymphocyte balance with decreased atopy as a result. This study was undertaken to determine whether tuberculin reactivity is inversely related to atopy in young adults vaccinated with BCG at the age of 14. METHODS: Men and women aged 20-44 years were tested using the adrenaline-Pirquet test with Norwegian produced synthetic medium tuberculin (n = 891). In addition, their serum total and specific IgE antibodies against mite, cat, timothy grass, mould and birch were measured. RESULTS: Of the 574 subjects with complete examinations, 64% had a positive adrenaline-Pirquet tuberculin test (> or =4 mm) and 27% exhibited IgE antibodies (> or =0.35 kU/l) to one or more of the five specific allergens. The geometric mean of total serum IgE in the population was 30.2 kU/l. Tuberculin reactivity and log IgE were not correlated (r = 0.043, p = 0.30). The mean tuberculin reactivity was 4.6 mm, 4.9 mm, and 5.0 mm in the lower, middle and upper tertile of IgE distribution (<14 kU/l, 14-61 kU/l, >61 kU/l). The prevalence of atopy, as assessed by either the presence of any of the five specific IgE antibodies or by each specific IgE antibody separately, did not differ between subjects with a positive and those with a negative tuberculin test. These results persisted after adjustment for age, sex, and smoking status in multivariate logistic regression analyses. CONCLUSIONS: In this young adult population, BCG vaccinated at the age of 14, no significant relationship between a positive tuberculin reaction and atopy was observed. If a true relationship had been found, our study suggests that it may be limited to populations immunised in early childhood when a substantial modulation of the immune system can occur.

Adult↗
PubMed2000

Maternal age at menarche and atopy among offspring at the age of 31 years.

BACKGROUND: Influences of female hormones on the occurrence of allergic disorders have been suggested. Age at menarche may be a marker of endogenous oestrogen levels. Data from a Finnish birth cohort followed to adulthood were analysed to determine whether there is any association between maternal age at menarche and the occurrence of atopy among offspring. METHODS: The study was conducted in 5188 subjects born in northern Finland for whom data collections were started during pregnancy and a follow up examination was completed at the age of 31 years. Atopy was determined by skin prick tests with cat, birch, grass, and mite extracts, and doctor diagnosed asthma was ascertained by questionnaire at follow up. Maternal age at menarche was obtained from perinatal data. Logistic regression models were used to adjust for maternal age, parity, smoking, season of birth, parental allergy, and measures of adiposity and socioeconomic status. RESULTS: The prevalence of atopy at the age of 31 years was lower in children whose mothers reached menarche at a later age, especially after age 15. Compared with children whose mothers started menarche at the age of 16 or over, the adjusted odds ratios of being atopic for children whose mothers started menarche younger than or at 12, 13, 14 and 15 years were 1.43 (95% CI 1.12 to 1.83), 1.29 (95% CI 1.03 to 1.60), 1. 15 (95% CI 0.93 to 1.42), and 1.19 (95% CI 0.95 to 1.48), respectively. Among girls, the offspring's own age at menarche was not significantly associated with atopy. CONCLUSION: Our results encourage further evaluation of the potential effect of maternal age at menarche on the later development of atopy and possible biological mechanisms.

Adolescent↗
PubMed2001

Respiratory symptoms, asthma, exercise test spirometry, and atopy in schoolchildren from a Lima shanty town.

BACKGROUND: Little is known about the associations between symptoms of asthma, pulmonary function tests, and atopy in developing countries. While asthma in children is often associated with atopy, some studies of wheezing illness have found little or no association, leading to suggestions that there are subgroups of wheezing illness. The ISAAC study recently reported that the prevalence of reported asthma symptoms in Lima, Peru was among the highest in the world, but did not report on the atopic status of the subjects. METHODS: A cross sectional survey was conducted of children aged 8-10 years who had previously participated in a cohort study of respiratory and diarrhoeal illnesses in infancy. Questionnaires were administered asking about respiratory symptoms and asthma diagnoses, pulmonary function tests were performed before and after exercise on a treadmill, and atopy was determined from skin prick tests and specific serum IgE levels. RESULTS: A total of 793 children participated in the survey. The prevalence of asthma related symptoms in the last 12 months was 23.2%, but only 3.8% of children reported a recent asthma attack. The mean differences in pretest percentage predicted forced expiratory volume in one second (FEV(1)) were 8.1% (95% CI 2.4 to 13.8) between children who did and did not report an asthma attack in the last 12 months, and 5.3% (95% CI 2.8 to 7.9) in children who did and did not report respiratory symptoms. The corresponding differences in mean percentage fall in FEV(1) after exercise were 3.1% (95% CI -1 to 7.1) and 5.1% (95% CI 3.4 to 6.8). Recent asthma or respiratory symptoms were not associated with atopy in this population (odds ratios 1.29 (95% CI 0.56 to 2.97) and 0.91 (95% CI 0.61 to 1.37), respectively). CONCLUSIONS: Most asthma in these children was unrecognised and mild. Asthma and asthma symptoms in this population do not seem to be related to atopy.

Asthma↗
PubMed2002

Age at childhood infections and risk of atopy.

BACKGROUND: It has been proposed that early age at exposure to common childhood infections is associated with a decreased risk of allergy. Previous studies on the possible association between allergy and infection with measles, mumps, rubella, and varicella have not been conclusive as most did not include information on exact age at exposure. The objective of our study was to investigate whether early age at exposure to these infections was associated with a decreased risk of atopy using information on exact age at infection. METHODS: The study population consisted of 889 pregnant women who participated in a national birth cohort study in Denmark and for whom detailed information on history of measles, rubella, varicella, and mumps before school entry (age 7 years) was available from school health records from Copenhagen. Atopic status was assessed serologically by a specific response to 11 common inhalant allergens using serum samples obtained from the women during pregnancy. RESULTS: Measles in the first year of life was associated with a higher risk of atopy than no measles before age 7 years (OR 3.36, 95% CI 1.47 to 7.68). There was no association between atopy and mumps, rubella, or varicella in the first 7 years of life or with measles acquired after the first year of life. The risk of atopy increased significantly with increasing number of childhood infections in the first 2 years of life (p(trend)=0.01). CONCLUSIONS: These findings do not support the suggestion that childhood exposure to measles, rubella, varicella, or mumps protects against atopy, even if acquired very early in life.

Adolescent↗
PubMed2003

Exhaled nitric oxide and asthma: complex interactions between atopy, airway responsiveness, and symptoms in a community population of children.

BACKGROUND: Exhaled nitric oxide (FE(NO)) is raised in asthmatic children, but there are inconsistencies in the relationship between FE(NO) and characteristics of asthma, including atopy, increased airway responsiveness (AR), and airway inflammation. The aim of this study was to investigate the relationship between FE(NO) and asthma, atopy, and increased AR in children. METHODS: One hundred and fifty five children (79 boys) of mean age 11.5 years underwent an assessment that included FE(NO) measurements, spirometric tests, inhaled histamine challenge, and a skin prick test. Blood was collected for eosinophil count. Current and past asthma like symptoms were determined by questionnaire. RESULTS: In multiple linear regression analyses FE(NO) was associated with atopy (p<0.001), level of AR (p = 0.005), blood eosinophil count (p = 0.007), and height (p = 0.002) but not with physician diagnosed asthma (p = 0.1) or reported wheeze in the last 12 months (p = 0.5). Separate regression models were conducted for atopic and non-atopic children and associations between FE(NO) and AR, blood eosinophils and height were only evident in atopic children. Exhaled NO was raised in children with a combination of atopy and increased AR independent of symptoms. CONCLUSION: Raised FE(NO) seems to be associated with an underlying mechanism linking atopy and AR but not necessarily respiratory symptoms.

Adolescent↗
PubMed1994

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.

Adolescent↗
PubMed1996

Atopy, bronchial hyperresponsiveness, and peak flow variability in children with mild occasional wheezing.

BACKGROUND: Children who suffer from recurrent wheezy episodes are often promptly classified as asthmatic. The aim of this study was to evaluate a population of mild wheezy children with repeatedly normal spirometric tests at rest for atopy, bronchial hyperresponsiveness, and peak expiratory flow variability. METHODS: Thirty nine children aged 6-16 years with 1-12 wheezy attacks during the previous year were recruited from a community paediatric primary health care clinic serving an urban Israeli population. The conditions for inclusion were a physician-diagnosed wheeze on auscultation and normal spirometric tests at rest on at least three occasions. Evaluation included skin prick tests for atopy and a physician-completed questionnaire. In addition, two tests of bronchial hyperresponsiveness (BHR) were performed--namely, exercise-induced bronchospasm and inhaled methacholine hyperresponsiveness--as well as diurnal variability of peak expiratory flow (PV). RESULTS: One or more tests of BHR/PV were positive in 27 (69%) but repeatedly negative in 12 (31%). In terms of frequency of wheezing attacks, atopy, and questionnaire responses, there were no differences between BHR/PV and non-BHR/PV children, with the exception of a history of chest radiography proven pneumonia (only noted in the BHR/PV group). Overall, evidence of atopy (mainly indoor allergens) was noted in 21 (56%) of those tested and parental smoking in 29 (74%) of households. Thirty-two (82%) of the children complained of an exercise-related wheeze, yet exercise-induced bronchospasm was only demonstrated in nine (23%). CONCLUSIONS: This selected group of wheezy children appears to be intermediate between a normal and clearly asthmatic population and, despite the recurrent wheezy attacks, some should probably not be classified as asthmatic by conventional criteria. Important aetiological factors in the symptomatology of these children may include parental smoking and atopy as well as other elements such as viral infections.

Adolescent↗
PubMed2005

Genetic and environmental factors in the immunopathogenesis of atopy: interaction of Helicobacter pylori infection and IL4 genetics.

BACKGROUND: Both genetic and environmental factors, e.g. early childhood infections, have a role in the pathogenesis of atopic diseases. OBJECTIVE: To examine simultaneously the strength and possible interactions of two known such factors, IL4 genetics and Helicobacter pylori infection, on the risk of atopy and asthma. METHODS: Gene polymorphism analyses and skin prick tests (SPT) were determined in 245 adult asthmatics and 405 nonasthmatic controls of population-based case-control study. SPTs were used as an indicator of atopy. H. pylori infection was verified by detecting anti-H. pylori IgG antibodies in sera. RESULTS: A significant negative association was seen between the presence H. pylori antibodies and SPT positivity (> or =1 positive reactions) in both asthmatics and controls (p = 0.002 and p = 0.025, respectively) but the effect of IL-4 polymorphism (SNP -590C/T) was nonsignificant in both groups (p = 0.071 and p = 0.072, respectively). However, IL4 genetics had an effect on susceptibility to H. pylori: asthmatics carrying the IL4 -590 allele T had a diminished risk to be H. pylori infected (OR 0.485 95%CI 0.287-0.819). This effect was not seen in controls. Logistic regression analysis indicated that H. pylori and IL4 effects on atopy risk are not interdependent. CONCLUSIONS: This study showed that the effect of H. pylori infection on atopy risk is stronger than that of IL4 genetics. There is no interaction between these factors on the pathogenesis of atopy suggesting that these factors have distinct immunopathogenetic mechanisms. However, the genetic effect may modify the role of infective agents by effecting on susceptibility to disease.

Aged↗
PubMed1996

IgE levels, atopy markers and hay fever in relation to age, sex and smoking status in a normal adult Swiss population. SAPALDIA (Swiss Study on Air Pollution and Lung Diseases in Adults) Team.

Within the framework of the SAPALDIA survey (Swiss study on Air Pollution and Lung Diseases in Adults), we studied the influence of sex, age and smoking habits on total serum IgE and allergen-specific IgE antibody concentrations (assessed by means of the Phadiatop test) and on the prevalence of hay fever. A total of 8,344 subjects aged 18-60 years, comprising 2,776 current smokers, 1,888 former smokers and 3,680 nonsmokers, were included in the study. Smokers had both a statistically significant (p<0.001) higher mean serum IgE concentration (geometric mean 39.7 kU/l), and a higher percentage (27.5%) of persons with elevated serum IgE (> 100 kU/l) than nonsmokers (27.2 kU/l; respectively 20.5%). The IgE level was significantly lower in women than men (p<0.001) in all smoking categories. The percentage of persons with positive atopic markers (positive Phadiatop test, positive skin prick tests to common inhalant allergens) and self-reported hay fever was significantly higher in nonsmokers than in smokers or former smokers. In Phadiatop positive (atopic) subjects, the IgE levels were highest, with a mean of 104.3 kU/l (99.0-109.8), and lowest in Phadiatop-negative nonsmokers at 27.2 kU/L (25.9-28.6). These findings correlate well with the current interpretation of total serum IgE values in screening for atopic diseases in adults (IgE < 20 kU/l: atopy improbable; IgE > 100 kU/l: atopy probable). In multivariate logistic regression models, the prevalence of positive Phadiatop tests, positive skin tests, and atopy decreased significantly with age. The odds of having a positive Phadiatop and skin test, or being atopic were found to decrease on average by 23.0, 21.1 and 21.0%, respectively, with every 10-year increase in age. With respect to smoking status, the odds ratios for the three atopic markers were significantly lower in current and former smokers than in nonsmokers. The prevalence of (self-reported) hay fever was highest in nonsmokers, intermediate in former smokers (odds ratio = 0.81, p<0.05) and lowest in current smokers (odds ratio = 0.76 in comparison to former smokers, p<0.01). The odds ratio of self-reported current hay fever decreased with age at an estimated average of 23% every 10 years. The decrease in former smokers might be slightly faster than in the other two categories. In conclusion, the present results demonstrated that tobacco smoking is associated with increased IgE levels and negatively related to atopy and hay fever. In addition, it is shown that atopy prevalence decreases with age.

Adolescent↗
PubMed1996

Atopy and nonspecific bronchial responsiveness. A population-based assessment. Spanish Group of the European Community Respiratory Health Survey.

The relative importance of specific immunoresponse in explaining nonspecific bronchial responsiveness (BR) has scarcely been examined. We provide quantitative estimates of the proportion of BR attributable to specific atopy to different common aeroallergens. We used data from a cross-sectional study on a random sample of the general population 20 to 44 yr of age from five Spanish areas. There were 1,816 participants who performed a methacholine challenge and had atopy assessed. BR was defined as a 20% or more fall in FEV1. Atopy was assessed by measuring serum-specific IgE or skin tests to cat, Dermatophagoides pteronyssinus, Cladosporium, Alternaria, timothy grass, olive, birch, Parietaria, or ragweed. The strongest associations between BR and specific IgE response were against timothy grass (prevalence rate ratio = 1.78; 95% confidence interval 1.2 to 2.6), Dermatophagoides pteronyssinus = 1.64 (1.2 to 2.2), and olive = 2.36 (1.5 to 3.7), all after adjustment by age, sex, area of residence, smoking, and a positive response to any of the other eight allergens measured. The population attributable risk of BR for a positive response to any of the nine allergens measured was 20.96% (10.2 to 43.2%) when adjusting for area of residence, age, sex, and smoking. Nonspecific bronchial responsiveness in the general population was found to be related to atopy against single specific allergens, but the population risk attributable to atopy may be lower than previously suggested.

Adult↗
PubMed1991

Interacting effects of atopy and bronchial hyperresponsiveness on the annual decline in lung function and the exacerbation rate in asthma.

The relationship between atopy and bronchial hyperresponsiveness (BHR) on the one hand and the annual rate of decline in FEV1 and the annual exacerbation rate on the other was studied in 71 adult patients with asthma during a period of 2 yr. Atopy (based on seven RAST tests) and BHR (PC20-histamine) were assessed at the start of the 2-yr follow-up period, and they were related to the decline in FEV1 (FEV1 slope) and the exacerbation rate. The results indicated that BHR was related to the FEV1 slope independently of the FEV1 level. The mean prebronchodilator FEV1 slope was -94 ml/yr (-39 to -149 ml/yr) in patients with PC20 less than or equal to 2 mg/ml and -21 ml/yr (+34 to -76 ml/yr) in patients with PC20 greater than 2 mg/ml. Atopy alone was not related to the FEV1 slope. However, in atopic patients BHR was related to a more pronounced FEV1 slope than in nonatopic patients. The slope of the postbronchodilator FEV1 was comparable with the slope of the prebronchodilator FEV1, which may indicate that the loss of FEV1 was not only due to increased bronchospasm but also to fixed obstruction. BHR and atopy were not associated with the exacerbation rate. Asthmatic patients with atopy and marked BHR should be looked upon as patients with a risk of developing progressive airflow obstruction.

Asthma↗
PubMed2004

Sex differences in the relation between body mass index and asthma and atopy in a birth cohort.

RATIONALE: Several studies have identified an association between asthma and obesity in women. It remains unclear if this association is due to genuine asthma or to symptoms caused by overweight, at what age the association develops, and whether it is confined to females. OBJECTIVE: To explore the relations between body mass index, asthma, and atopy in a birth cohort of approximately 1,000 individuals. METHODS: Information on asthma and measurements of lung function, airway responsiveness, and atopy were obtained on multiple occasions between ages 9 and 26. Associations between these outcomes and body mass index were analyzed using generalized mixed linear regression models. Further analyses adjusted for potential covariates including breastfeeding, birth order, parental asthma, and personal and family smoking history. MAIN RESULTS: Body mass index was positively associated with asthma, wheeze, asthma treatment, atopy, immunoglobulin E, and inversely with the FEV(1)/FVC ratio in females. There was no significant association with airway responsiveness to methacholine or salbutamol. There was little evidence of an association between body mass index and asthma or atopy in males. Analyses adjusting for potential covariates showed similar findings. Asthma was not associated with a raised body mass index in childhood and childhood asthma did not lead to being overweight as an adult. CONCLUSIONS: A raised body mass index is associated with asthma and atopy in women but not men. Population attributable fraction calculations estimate that 28% (95% confidence interval 7-45) of asthma developing in women after age 9 is due to overweight.

Adolescent↗
PubMed2001

Identification and association of polymorphisms in the interleukin-13 gene with asthma and atopy in a Dutch population.

Asthma and atopy are related conditions that may share similar genetic susceptibility. Linkage studies have identified a region on chromosome 5q that contains biologic candidates for both asthma and atopy phenotypes, including several proinflammatory cytokines. Interleukin (IL)-13, one of the candidate genes in the region, is directly involved in the regulation of immunoglobulin E and has been associated with both asthma and atopy. We sought to identify new polymorphisms in the IL-13 gene, and evaluated the involvement of a subset of these variants in asthma and atopy in a case-control study using probands and spouses from a Dutch asthma family study. IL-13 was sequenced in 20 probands and 20 unaffected spouses, and 10 polymorphisms were identified, four novel and six previously reported. Three single nucleotide (nt) polymorphisms (SNPs) were detected in the 5'-promoter region, two in intron 1, and five in exon 4. Only one of the exon 4 SNPs resulted in an amino-acid change (Arg130Gln). We analyzed three SNPs in IL-13 in an extended group of 184 probands and their spouses: one in the promoter region (-1111), the Arg130Gln (nt position 4257), and a 3' untranslated region SNP (nt position 4738). The most significant associations were observed to asthma (P = 0.005), bronchial hyperresponsiveness (P = 0.003), and skin-test responsiveness (P = 0.03) with the -1111 promoter. These results provide evidence that variation in the IL-13 gene is involved in the pathogenesis of asthma and atopy. Further investigation is required to determine which specific alleles or combination of alleles contribute to these phenotypes, and the possible downstream effects of the resulting change in IL-13 levels or activity.

Adult↗
PubMed2002

The effects of respiratory infections, atopy, and breastfeeding on childhood asthma.

The objectives of the present study were to quantify the association of atopy and respiratory infections with asthma, and exclusive breastfeeding with respiratory illness, atopy and asthma in children. A cohort study of 2,602 children enrolled prior to birth and followed prospectively, provided data on respiratory illness, the method of feeding in the first year of life, as reported on a prospective diary card, and current asthma at the age of 6 yrs (defined as doctor-diagnosed asthma with wheeze in the last year or cough without a cold, and currently taking either preventer or reliever asthma medication), as reported by parental questionnaire. Atopy was defined by a positive skin-prick test assessed at the age of 6 yrs. Wheezing lower respiratory illness (LRI) in the first year of life, particularly multiple episodes of wheezing LRI, increased the risk for current asthma in both nonatopic (odds ratio (OR) 4.10, p< or =0.0005) and atopic children (OR 9.00, p< or =0.0005), but did not increase the risk for atopy. In contrast, up to three upper respiratory tract infections demonstrated a negative association and four or more a positive risk for current asthma in unadjusted (p=0.006) and adjusted (p=0.057) analysis. Following adjustment, exclusive breastfeeding for <4 months was associated with an increased risk for current asthma (OR 1.36, 95% confidence interval 1.00-1.85, p=0.047). Wheezing lower respiratory illness in the first year of life and atopy are independently associated with increased risk for current asthma at the age of 6 yrs, suggesting that their effects are mediated via different causal pathways and that these risk factors are multiplicative when they operate concomitantly within individual children. Exclusive breastfeeding protects against asthma via effects on both these pathways, as well as through other as yet undefined mechanisms.

Asthma↗
PubMed2003

Can early infection explain the sibling effect in adult atopy?

Atopy is strongly and inversely related to family size, a pattern which is plausibly assumed to reflect a protective effect of early infection. The current study tested this hypothesis by case-referent analysis of an adult cohort in the UK. The study established that atopy, defined by prick tests to common aeroallergens, was less common among those from larger families after adjustment for potentially confounding factors. In particular, a higher number of brothers appeared to offer protection. The current authors attempted to explain this distribution by examining contemporary family-doctor records of early childhood infections; and by a number of other indirect indices of early-life "hygiene". The sibling effect was unexplained by evidence of infection with either hepatitis A or Helicobacter pylori, or by counts of infections or antibiotic prescriptions in early life. There was a significant and independent negative association between the number of gastrointestinal infections before the age of 5 yrs and the odds of atopy. Dog ownership and home moving in early life also displayed potentially protective associations. Although the current study replicates the finding that atopy is inversely associated with family size this could not be explained by documentary or serological evidence of early infection. The findings support the suggestion that the "sibling effect" in atopy may not simply reflect protection by early infection.

Adult↗
PubMed1995

Outcome of wheeze in childhood: the influence of atopy.

We have previously demonstrated that the adult outcome of childhood asthma differs from that of wheeze occurring only in the presence of infection. This paper examines the role of atopy in relation to outcome. We investigated the atopic status, current symptoms and bronchial reactivity to methacholine of 235 subjects aged 34-40 yrs, originally classified at age 10-15 yrs as having asthma (asthma group), wheeze only in the presence of infection (wheezy group), or no respiratory symptoms (comparison group). Subjects from the original asthma group were more likely to be atopic as defined by skin test reactivity, total serum immunoglobulin E (IgE) measurement or specific IgE radio allergosorbent test (RAST) measurement than those from the wheezy group. The wheezy group differed significantly from the reference group only in RAST results, when other variables were taken into account. In a logistic regression model, the important independent predictors for adult wheezing symptoms were original group, atopy and current smoking. Methacholine responsiveness was independently associated with original group (the asthma group were more likely to respond positively), atopy and female gender. The results suggest that atopy is an important predictor for wheeze and bronchial hyperreactivity in middle age. However, the difference in outcome for children who had asthma compared to those who had wheeze only in the presence of infection cannot be explained by atopy alone.

Adolescent↗
PubMed1999

Lower prevalence of asthma and atopy in Turkish children living in Germany.

Ethnic origin has been reported to affect the prevalence of atopic diseases in several studies in different parts of the world. However, little is known about the prevalence of asthma and atopy in immigrants living in Europe. The objective of this study was to evaluate the prevalence of asthma and atopy in Turkish children living in Germany and to investigate the role of ethnic origin on the development of asthma and atopy in this population. In a cross-sectional survey the prevalence of physician-diagnosed asthma, atopy, skin-prick tests and bronchial hyperresponsiveness (BHR) to cold dry air challenge was assessed in 7,445 school children aged 9-11 yrs, living in Munich, south Germany. Questionnaires were distributed to the parents for self-completion and children underwent skin prick tests and cold air hyperventilation challenge. The Turkish children showed a significantly lower prevalence of asthma (5.3 versus 9.4%, p<0.05) than their German peers. Furthermore, atopy, as assessed by skin prick tests (24.7 versus 36.7%, p<0.001) and BHR (3.9 versus 7.7%, p<0.001), was less common in Turkish children. In multivariate regression models controlling for potential explanatory factors, Turkish origin still showed a significantly lower risk of developing asthma, atopic sensitization and BHR. The prevalence of childhood asthma was therefore shown to be lower in Turkish children living in Germany than in Turkey. These findings suggest that the lower prevalence of asthma and allergy in Turkish children living in Germany might be attributable to a selection bias affecting the parents of these children, as healthy individuals may have decided to come to Germany for work.

Age Distribution↗
PubMed2001

Environmental tobacco smoke, parental atopy, and childhood asthma.

We hypothesized that the joint effect of genetic propensity to asthma and exposure to environmental tobacco smoke on the risk of childhood asthma is greater than expected on the basis of their independent effects. We performed a population-based 4-year cohort study of 2,531 children born in Oslo, Norway. We collected information on the child's health and environmental exposures at birth and when the child was 6, 12, 18, and 24 months and 4 years of age. The outcomes of interest were bronchial obstruction during the first 2 years and asthma at the age of 4 years. Parental atopy was defined as a history of maternal or paternal asthma or hay fever. Exposure to environmental tobacco smoke was defined on the basis of questionnaire information on household smokers at birth. In logistic regression analysis adjusting for confounding, parental atopy alone increased the risk of bronchial obstruction [odds ratio 1.62; 95% confidence interval (CI) 1.10-2.40] and asthma (1.66; 95% CI, 1.08-2.54). In children without parental atopy, there was little effect of exposure to environmental tobacco smoke on bronchial obstruction (1.29; 95% CI, 0.88-1.89) and asthma (0.84; 95% CI, 0.53-1.34). The presence of parental atopy and exposure had a substantial effect both on bronchial obstruction (2.88; 95% CI, 1.91-4.32) and asthma (2.68; 95% CI, 1.70-4.22). The results are consistent with the hypothesized joint effect of parental atopy and exposure to environmental tobacco smoke. This phenomenon--denoted as effect modification of environmental exposure by genetic constitution, or gene by environment interaction--suggests that some genetic markers could indicate susceptibility to environmental factors.

Adult↗