Epidemiological Study of the Genetics and Environment of Asthma, Bronchial Hyperresponsiveness, and Atopy

Abstract

The Epidemiological Study of the Genetics and Environment of Asthma (EGEA) combined a case-control study and a family study. The total sample of 1,854 consisted of 348 patients with asthma selected through chest clinics and 416 control subjects and nuclear families ascertained through the cases. The protocol included standardized questionnaires, bronchial responsiveness, allergen skin-prick tests according to international protocols, total serum immunoglobulin E (IgE) level measurements, and blood eosinophilia. Criteria used to select subjects with asthma and determine asthma status of relatives for affected sibling pair linkage analysis are described. Based on figures from the 348 asthma cases of the EGEA study, issues relative to the definition of severe asthma and intermediate phenotypes such as bronchial responsiveness and allergic markers are discussed. Given the phenotypic heterogeneity involved, relevant phenotypes that may lead to the detection of genetic factors will depend on the hypothesis tested. Standardization of primary data and subphenotypes is a prerequisite for pooling data, which will be needed in the future to better understand the genetics and environmental factors of asthma.

A haplotype of the human CXCR1 gene protective against rapid disease progression in HIV-1+patients

“…All patients enrolled in the study gave informed consent. The data on 471 CTR subjects of the same ethnic origin with unknown HIV status were obtained as part of the Epidemiological Study on the Genetics and Environment of Asthma (EGEA) study of asthma (29). DNA was obtained from fresh peripheral blood mononuclear cells or from EBV-transformed cell lines.…”

Scores of asthma and asthma severity reveal new regions of linkage in EGEA study families

“…The protocol for the EGEA data collection has been described elsewhere [7,8,10]. Subjects answered a detailed questionnaire regarding respiratory symptoms and treatment based on international standardised questionnaires.…”

“…Ventilatory function was assessed by means of the FEV1 measured before bronchodilator use, according to a previously described protocol [10], and expressed as a percentage of the predicted value based on age, height and sex [8].…”

“…First, these results may be due to a reduction in asthma misclassification. Whereas asthmatic probands were defined using a very strict procedure and recruited in chest clinics [10], the definition of asthma in siblings was less specific, although attention was paid to items such as bronchial hyperresponsiveness, treatment or hospitalisation in the confirmation of asthma. In this context, a categorical variable may decrease such potential misclassification bias.…”

Sex-specific effect of IL9 polymorphisms on lung function and polysensitization

“…32,33 Probands and their first-degree relatives answered a detailed questionnaire regarding respiratory symptoms and treatment based on International Standardized Questionnaires. 32,33 A total of 388 families were ascertained through at least one asthmatic proband.…”