Bronchial hyperresponsiveness in two populations of Australian schoolchildren. II. Relative importance of associated factors.
ABSTRACT In a cross-sectional study of 2363 schoolchildren living in two rural areas of New South Wales, we used a questionnaire to collect details of sex, area of residence, social class, early respiratory illness (ERI), parental history of asthma and recent upper respiratory tract infection (URTI), and we used skin-prick tests to measure atopic status. The relative importance of these factors on the likelihood of children having bronchial hyperresponsiveness (BHR) was assessed using a linear modelling analysis. The extent to which these factors affected the severity of BHR was also examined. We found that social class or recent URTI had no association with BHR, that sex and area of residence (inland or coastal) had a small association and that a history of early respiratory illness, a history of asthma in either parent, and atopic status had an important association with BHR. Atopic status was the most important factor. The proportion of children with atopy, with ERI or with parental asthma increased as the severity of BHR increased. The odds ratio for moderate or severe BHR doubled if either ERI or parental asthma was present in addition to atopy and there was a six-fold increase if all three factors were present together. The identification of these risk factors makes it possible to predict which children in the community are most likely to have BHR, and which children are at high risk for having more severe levels of BHR.
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ABSTRACT: This study was undertaken to examine the relationship between respiratory illness in early childhood and asthma in adolescence and young adulthood (age group 10-23 years). The study population comprised 277 boys and 274 girls, born between 1967 and 1978 and registered from their birth to the year of study (1989) on the practice lists of the four general practices taking part in the continuous morbidity registration project (CMR) at the University of Nijmegen in the Netherlands. Details of all episodes of respiratory morbidity presented in the first five years of life and registered in the project were collected together with data on current respiratory status determined by means of a questionnaire on respiratory symptoms, spirometry and a histamine-challenge test. Sixteen per cent of the study group were diagnosed as having asthma. Only asthma and acute bronchitis in early childhood were significantly associated with asthma at age 10-23 years. Asthma in adolescence and young adulthood is related to asthma and acute bronchitis in early childhood. This study supports the view that this could be a causal relationship although an alternative explanation could be misclassification. The results provide no indication that upper respiratory tract infections are associated with the development of asthma in adolescence or young adulthood.British Journal of General Practice 03/1994; 44(379):73-8. · 2.36 Impact Factor
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ABSTRACT: Sheepskin bedding might increase house dust mite exposure and so explain some of the increasing prevalence of severity of childhood asthma. Relationships between use of different types of bedding, and diagnoses of asthma, symptoms of wheezing, skin prick test evidence of house dust mite sensitivity, and airway responsiveness to methacholine, were examined retrospectively in a birth cohort of children followed longitudinally to age 15 years. In the whole cohort, no associations were identified to suggest a causal relationship between use of any type of bedding and development of features of asthma. Although not an a priori hypothesis, we noted that among children with a family history of atopic disease, those who were house dust mite sensitive were more likely to have used an innerspring mattress (29.6% vs 10.2% who had not used an innerspring mattress, p = 0.005). In this subgroup, increased airway responsiveness and mite sensitivity were significantly associated with use of innerspring mattresses, although whether this is a causal or secondary association is not certain. Use of a sheepskin in the bed in early childhood was not an additional risk factor for the development of asthma.Australian and New Zealand journal of medicine 01/1995; 24(6):687-92. DOI:10.1111/j.1445-5994.1994.tb01784.x
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ABSTRACT: The relationship of bronchial responsiveness (BR), assessed by methacholine challenge, to serum IgE, baseline ventilatory function, and symptoms or diagnoses suggesting an atopic disorder were examined in 522 11-year-old New Zealand children. BR was assessed by the presence or absence of a PC20 25 mg/ml or less and by calculating a continuous index of the decline of the FEV1 during the methacholine test. The latter facilitated multivariate analyses and revealed significant relationships to predictor variables even in those considered "nonresponsive" by PC20 criteria. There was a close relationship of BR to the baseline FEV1/vital capacity ratio, seen even in patients with known asthma, but this relationship was seen only in subjects with at least moderate levels of serum IgE. There was a less close relation of BR to percent predicted FEV1, but this persisted even after accounting for the FEV1/vital capacity ratio and was present regardless of the level of serum IgE. Reported asthma was associated with increased BR independent of all other factors, but other diagnoses and symptoms contributed relatively little to the prediction of BR once the serum IgE and lung function were taken into account. The overall results are compatible with the concept that IgE is a critical factor in the development of bronchial responsiveness in childhood.Journal of Allergy and Clinical Immunology 10/1992; 90(3 Pt 1):376-85. DOI:10.1016/S0091-6749(05)80018-1 · 11.25 Impact Factor