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Notes: Background  The prevalence of atopic diseases is increasing in western countries, and environmental exposures in childhood may influence development of atopic sensitization.Objective  To investigate the prevalence and predictors of atopy among young Danish adults.Methods  Of 940 invited subjects, aged 19–29 years, complete data were obtained from 525 (56%) subjects. All completed a questionnaire concerning asthma, rhinitis, preschool nursery care, smoking habits, family size, education and employment. A skin prick test was performed, and pulmonary function was measured using standard techniques. Atopy was defined as a positive skin prick test.Results  The frequency of atopy was 32% (males 43% vs. females 23%, P 〈 0.001). We found a positive association between atopy and atopic dermatitis (P 〈 0.05), rhinitis (P 〈 0.001), itching when eating nuts (P 〈 0.001) and current asthma (P 〈 0.001). There was an inverse relation between atopy and having furred pets in childhood (P 〈 0.05), passive smoking in childhood (P 〈 0.01) and current passive smoking (P 〈 0.05). An increasing number of siblings was inversely related to atopy to grass (P 〈 0.05); however, only an increasing number of older siblings seemed to protect from atopy to grass (P 〈 0.05). Subjects who had never attended a day-care centre had significantly more atopy to grass (P 〈 0.05). No significant association was found between atopy and airway infections requiring hospitalization before the age of 5 years, or between atopy and bedroom sharing in childhood.Conclusion  Atopy is common among young Danish adults, especially in males. Participants were less likely to be atopic, especially to grass allergen, if they came from large families, had kept furred pets as children, and had been exposed to tobacco smoke.

Notes: To investigate the bronchial response to exercise, we studied a random sample of 494 children and adolescents, aged 7–16 years, from Copenhagen. Exercise challenge consisted of steady running on a 10% sloping treadmill for 6 min in a climate chamber. Furthermore, in 464 subjects a histamine challenge test was also performed. Of the 494 subjects studied, 81 (16%) had at least 10% and 30 (6%) at least 15% reduction in FEV1 within 15 min after exercise. Twenty-nine (6%) subjects had bronchial hyperresponsiveness to both histamine and exercise, 48 (10%) subjects had bronchial hyperresponsiveness to exercise, but histamine responsiveness within the normal range, whereas 340 (73%) subjects had neither bronchial hyperresponsiveness to exercise nor inhaled histamine. With regard to the presence of asthma defined as substantial exercise induced bronchoconstriction (Δ-FEV1≥10%), exercise testing may not be appropriate for identifying clinical asthma in a random sample, because the highest predictive value of a positive lest was 25%. On the other hand, a history of clinical asthma was frequently associated with increased bronchial responsiveness to exercise (77%). In conclusion, 16% of a random sample of children and adolescents had abnormal bronchial responsiveness to exercise (ΔFEV1≥10%), 6% of the subjects had a ΔFEV1≥15%. Furthermore, because of a low predictive value of a positive test, the exercise challenge test has only a supplementary role in the detection of clinical asthma in population samples.

Notes: To study the prevalence and possible predictors of bronchial responsiveness we examined a cross-section of 527 children aged 7–16 years from Copenhagen. The method used included an interview with the child and the parents, skin prick test with common allergens and se-IgE. Bronchial responsiveness was measured by a histamine inhalation test. We found that 79 (16%) of the children had bronchial hyperresponsiveness (BH), defined as a 20% fall in FEV1 with a provoking concentration of histamine (PC20) at 8 mg/ml or less. Atopic symptoms defined as asthma, rhinitis or eczema were significantly (P 〈 0.001) correlated to BH both in prevalence and degree of BH. None of the children with urticaria had BH. The degree of bronchial responsiveness was also significantly influenced (P 〈 0.001) by family disposition to atopy, whereas we found no correlation between BH and “passive” smoking, specific skin test in unselected children, or elevation of IgE in children without atopic symptoms. We conclude that BH is severest in children with asthma, independent of elevated IgE or positive skin prick test. Children with rhinitis, dermatitis, or asymptomatic BH have the same degree of BH; this differed from that in children with asthma.

Notes: The ability of the new generation H1-receptor antagonist, astemizole, to prevent histamine-induced airway obstruction and exercise-induced asthma (EIA) was studied in 20 children with asthma. The study was a randomised clinically controlled trial of oral astemizole versus placebo in a cross-over study. In each of the two treatment periods the children were tested at days 0, 6, 15 and 22 of therapy. The two treatment periods were separated by a washout period of 50 days, and at each visit a bronchial challenge with increasing concentrations of histamine followed by an exercise test was performed, and peak flow and asthmatic symptom score were recorded daily. The children tolerated significantly higher mean concentrations of histamine when treated with astemizole compared with placebo (P 〈 0.001). Astemizole postponed the response to exercise, but no change in the maximal response was found. No differences between the treatment periods were found regarding frequency of asthmatic symptoms or the daily recording of peak flow.

Notes: Background: Patients with birch and grass allergy often suffer from oral allergy symptoms when ingesting cross-reacting fresh fruits and vegetables. However, fruit and vegetable allergen extracts are often readily degradable or contain clinically irrelevant cross-reacting epitopes, resulting in diagnostic discrepancies when fruit and vegetable allergic reactions are evaluated. The risk of using nonstandardized fresh food extracts for skin testing may also be of concern.The objective was to compare and evaluate the clinical utility of selected recombinant grass and birch cross-reacting food allergens with fresh and commercial melon, hazelnut, and apple extracts. Methods: Thirty-six grass- and or birch-allergic patients and 17 control subjects consented to participate in the study. All subjects were skin prick tested and had basophil histamine-release tests done with fresh fruits and various extracts of hazelnut, apple, and melon. The diagnosis of oral allergy syndrome was confirmed by oral challenges. In addition, histamine release to recombinant Bet v 1 and Bet v 2, and recombinant Phl p 1 and Phl p 2, Phl p 5 was performed. Results: The skin prick test with fresh hazelnut, apple, and melon showed sensitivities of 0.97, 0.92, and 0.89, respectively. The corresponding specificities were 0.78, 0.72, and 0.82, respectively. In contrast, the histamine-release test with hazelnut, apple, and melon gave sensitivities of 0.87, 0.71, and 1.00, respectively. The corresponding specificities were 0.65, 0.93, and 0.43. The skin prick test showed excellent negative predictive value (〉90%). No added value of recombinant allergen testing was noted. Oral challenge did not result in severe systemic reactions, and no systemic reactions were observed with skin prick tests with fresh fruits. Conclusions: The skin prick test showed an almost optimal diagnostic value with a satisfactory sensitivity (〉89%) and excellent negative predictive value with fresh fruits. When the skin prick test with fresh nut and apple cannot be performed, histamine release is a diagnostic alternative. Histamine release with melon showed lack of specificity. This was probably due to extensive IgE cross-reactivity with pollen, since these patients also responded to recombinant Phl p 1 and Bet v 1. Skin testing and challenges with fresh fruits were safe.

Notes: Background: The prevalence of self-reported symptoms of allergic rhinitis is increasing in many countries, but the reasons for this trend are not well understood. Data from a 6-year follow-up study of a population sample of children and adolescents (n=408), aged 7–17 years at enrolment in 1986, were analyzed to investigate the prevalence and predictors of self-reported rhinitis. Methods: Case history was used to assess the presence or absence of rhinitis (sneezing and running or blocked nose not associated with a cold), asthma, and eczema. Pulmonary function, skin prick test reactivity, and airway responsiveness to histamine were measured in all participants; a screening test for IgE antibodies to common allergens (Magic Lite SQ, Allergy Screen, ALK, Denmark) was performed in 237 (58%) of the participants. Results: The point prevalence of rhinitis increased from the first to the second survey, 14% and 22%, respectively; 54 (13%) of the subjects reported rhinitis only at the second survey (new rhinitis). Confining the analysis to participants without symptoms of rhinitis at the first survey showed that self-reported eczema (relative risk [RR] 2.3, 95% confidence interval [CI] 1.2–4.7), airway hyperresponsiveness (RR 2.5, CI 1.8–3.0), atopy to grass pollen (RR 2.6, CI 1.7–3.3), atopy to dog dander (RR 2.4, CI 1.6–3.3), and atopy to house-dust mite (RR 2.7, CI 1.4–5.2) at the first survey predicted an increased risk of the presence of rhinitis at the second survey. A positive Allergy Screen test at enrollment was associated with an increased risk of self-reported rhinitis at follow-up (RR 2.4, CI 1.4–3.4). Conclusions: This longitudinal population study of children and adolescents showed an age-related increase in the point prevalence of self-reported rhinitis; furthermore, sensitization to common aeroallergens, airway hyperresponsiveness, and the presence of self-reported eczema were significantly associated with an increased risk of subsequent development of rhinitis.

Notes: The distribution of total serum-IgE and factors of importance for the level of IgE was studied in a random sample of 508 children and adolescents, aged 7–16 years, from Copenhagen. A detailed history about asthma, rhinitis, dermatitis and urticaria was obtained, and a physical examination, skin prick test with 9 common allergens, lung function test, bronchial challenge with inhaled histamine and exercise, and measurement of IgE (kU/1) were performed. The distribution of IgE among children and adolescents was found to exhibit a log normal distribution and a positive skin prick test, allergic symptoms, a family history of allergic diseases, age and smoking were found to be significantly related to an increased level of IgE. No relationship was found between increased bronchial responsiveness and IgE. The geometric mean of “normal” values of IgE (* 1 SD and *2 SD) of the Danish children and adolescents was 18 kU/1 (*4.7, * 18.2), suggesting that normal IgE values were within 330 kU/1. Measurement of IgE as the only screening for allergic disease is unreliable, as the predictive value of an elevated IgE in population samples was found to be 50%, whereas misclassification (1-specificity) of asymptomatic subjects as allergic because of an increased IgE was low (4%). In conclusion, total IgE is highly influenced by allergen skin reactivity. Further, this study suggests that normal IgE values were within 330 kU/1, although the range was wide.

Notes: Ulrik CS, Backer V, Bach-Mortensen N. Bronchodilating effect of ipratropium bromide inhalation powder and aerosol in children and adolescents with stable bronchial asthma.The purpose of this study was to compare the bronchodilating effect of ipratropium bromide (IB) administered by a conventional Ingelheim powder device system (IPI) and by a metered dose inhaler (MDI) in children and adolescents with stable bronchial asthma. Seventy patients, aged 7 to 16 years, with stable bronchial asthma from our outpatient clinic were tested for bronchial responsiveness to inhaled IB. Fifteen (21%) of the 70 subjects were found to have a substantial bronchial response to inhalation of 40 γg IB, i.e. at least 15% increase in FEV1 30 min after inhalation; the remaining 55 subjects had 〈15% increase in FEV1. No relationship between severity of asthma, age or sex and bronchial responsiveness to inhaled IB was found. Among the 15 subjects who had substantial bronchial response to IB, the increase in FEV1 after inhalation of fenoterol tended to be greater than the response to inhaled IB, although this did not reach statistical significance. Responders, i.e. subjects who had at least 15% increase in FEV1 after inhalation of IB, took part in a double-blind, cross-over study of the bronchodilating effect of 40 γg IB delivered by IPI and MDI. We found no significant differences in the bronchodilating effect during a 6-h follow-up. Maximum bronchodilating effect of IB was reached after 30 min and the maximum response lasted for 90 min. No side or adverse effects were observed following inhalation of IB. We conclude that before starting treatment with ipratropium bromide for bronchial asthma in children and adolescents, the patients should be tested for bronchial responsiveness to inhaled IB to find out whether they are responders or nonresponders; and further that, among responders, inhalation of powder is as effective as inhalation from a dosis-aerosol.

Notes: The purpose of this study was to investigate whether recent and previous subclinical viral respiratory infection can explain the presence of increased bronchial responsiveness to histamine. We studied a randomly selected population of 495 children and adolescents, aged 7–16 years, from Copenhagen. If the subjects had had symptoms of respiratory infection recently, the examination was postponed for at least 6 weeks. Bronchial hyperresponsiveness (BHR) to inhaled histamine was found in 79 (16%) of the subjects, of whom 28 had asthma. Forty-eight subjects (10%) had increased levels of serum IgM antibodies against either parainfluenza, influenza, adenovirus, or respiratory syncytial virus (RSV), reflecting a recently acquired infection. No association between BHR and antibodies against respiratory viruses was found, as 7 (8.9%) of the 79 subjects with BHR and 41 (9.9%) of the 416 subjects without BHR had viral antibodies. Furthermore, no association between degree of bronchial responsiveness and viral antibodies was found. Moreover, 251 individuals (51%) had signs of earlier RSV infection, i.e. IgG antibodies against RSV. No relationship was found between age of the subjects and the presence of antibodies against either respiratory viruses in general or IgG-RSV. No relationship was found between the presence of antibodies against RSV and BHR; furthermore, evidence of earlier RSV infection was unrelated to the level of lung function and degree of bronchial responsiveness. We conclude that increased bronchial responsiveness in asymptomatic, unselected schoolchildren and adolescents is not likely to be caused by recent or previous viral respiratory infections.