[Genetic and environmental factors of asthma and allergy: Results of the EGEA study]. / Facteurs génétiques et environnementaux de l'asthme et de l'allergie: synthèse des résultats de l'étude EGEA.

INTRODUCTION AND METHODS: The EGEA study (epidemiological study on the genetics and environment of asthma, bronchial hyperresponsiveness and atopy), which combines a case-control and a family-based study of asthma case (n=2120 subjects) with three surveys over 20 years, aims to identify environmental and genetic factors associated with asthma and asthma-related phenotypes. We summarize the results of the phenotypic characterization and the investigation of environmental and genetic factors of asthma and asthma-related phenotypes obtained since 2007 in the EGEA study (42 articles). RESULTS: Both epidemiological and genetic results confirm the heterogeneity of asthma. These results strengthen the role of the age of disease onset, the allergic status and the level of disease activity in the identification of the different phenotypes of asthma. The deleterious role of active smoking, exposure to air pollution, occupational asthmogenic agents and cleaning products on the prevalence and/or activity of asthma has been confirmed. Accounting for gene-environment interactions allowed the identification of new genetic factors underlying asthma and asthma-related traits and better understanding of their mode of action. CONCLUSION: The EGEA study is contributing to the advances in respiratory research at the international level. The new phenotypic, environmental and biological data available in EGEA study will help characterizing the long-term evolution of asthma and the factors associated to this evolution.

Under-estimation of self-reported occupational exposure by questionnaire in hospital workers.

OBJECTIVES: The aim of the study was to determine whether self-reported occupational exposure to cleaning/disinfecting agents in hospital workers is accurate, in comparison to expert assessment, taken to be the gold standard. METHODS: In the Epidemiological Study of the Genetics and Environment of Asthma (EGEA), participants were interviewed on occupation with a specific questionnaire for hospital workers regarding tasks and cleaning/disinfecting agents. Two estimates of exposure were available: self-report and expert assessment. The expert assessment involved a standardised procedure to estimate intensity, frequency and probability of exposure for each job. The present analysis focused on eight exposures: formaldehyde, glutaraldehyde, bleach/chlorine, alcohol, quaternary ammonium components, ammonia, sprays and latex gloves. Agreement and differences between self-reported and expert estimates were studied by kappa and phi coefficients and McNemar tests, respectively. RESULTS: In the survey of 1571 adults, 176 ever hospital workers (327 occupations) with both self-reported and expert exposure assessments were studied. An underestimation of self-reported exposure was observed especially for formaldehyde (26.5% vs 32.7%, p=0.01), ammonia (7.4% vs 18.8%, p<0.0001), alcohol (64.9% vs 93.0%, p<0.0001) and quaternary ammonium components (16.6% vs 70.9%, p<0.0001), compared to expert assessment. CONCLUSION: Occupational exposure to disinfecting/cleaning agents is common and high in hospitals. A large underestimation of self-reported exposure and a lack of knowledge of product components was observed. Our results show the relevance of expert assessment in epidemiological studies to limit measurement bias. This work underlines the need for health education programmes on the occupational risks induced by these types of products.

Inhaled formaldehyde exposure: effect on bronchial response to mite allergen in sensitized asthma patients.

BACKGROUND: Formaldehyde, an indoor air pollutant, is known to be an irritant and an etiologic factor in occupational asthma. An epidemiologic study suggests that it may also increase the risk of childhood asthma for concentrations above 60 microg/m(3). AIM: To evaluate the influence of pre-exposure to low-dose formaldehyde (100 microg/m(3) in 30 min according to the World Health Organization's recommended maximum value for indoor environments) on bronchial response to Dermatophagoides pteronyssinus. METHOD: Nineteen asthmatic subjects were included. Each subject underwent a mite allergen bronchial challenge test immediately after a standardized exposure in a chamber to formaldehyde or air (random order). Induced sputum were collected 24 h before and after mite challenge. RESULTS: After formaldehyde inhalation, patients developed an immediate bronchial response at a significantly lower dose of mite allergen than after air exposure (the geometric mean PD(20) for Der p 1 was 34.3 ng after formaldehyde and 45.4 ng after placebo, P = 0.05). The late-phase reaction, expressed as the maximum fall in forced expiratory volume in 1 s (FEV(1)) from baseline, was significantly higher after formaldehyde (15%vs 11%, P = 0.046). CONCLUSION: Our study demonstrated that exposure to low levels of formaldehyde significantly enhanced bronchial responsiveness to mite allergen in mite-sensitized subjects with asthma.

[The bronchial response to inhaled formaldehyde]. / Le formaldéhyde inhalé et la réponse bronchique.

INTRODUCTION: Formaldehyde is an ubiquitous indoor chemical polutant. Occupational exposure to high concentrations has revealed its irritant and allergenic potential. Nevertheless, domestic exposure to low concentrations may also have an effect on respiratory health in a non-specific way, just as has been found for other pollutants. STATE OF KNOWLEDGE: Potentiation of the response to allergens has been observed in animals and children. This effect has also been found on respiratory symptoms, with a 39% increase in the risk of asthma for a domiciliary exposure of more than 60 microgrammes.m(-3). We have recently been able to show, in a study with asthmatics sensitised to house dust mite, that the response to allergen provocation was increased following a 30 minutes exposure to 100 microgrammes.m(-3) formaldehyde. VIEWPOINT AND CONCLUSIONS: All the data show that mild exposure to formaldehyde in the home is sufficient to provoke sensitisation and also an aggrevation of symptoms in patients with allergic asthma. Taking into account the published evidence it is advisable that the concentrations of formaldehyde in domestic products should be made known in order to improve domiciliary air quality.

[Markers of environmental tobacco smoke (ETS) exposure]. / Les marqueurs d'exposition au tabagisme passif.

INTRODUCTION: Tobacco smoke is one of the most common air pollutants found in the indoor environment. Passive smoking is defined as the involuntary inhalation of tobacco smoke present in the air. This article examines the advantages and limitations of the methods that are available to measure environmental tobacco smoke exposure. STATE OF THE ART: Passive smoking can be assessed either by measuring tobacco smoke pollutants found in the air directly or by using biomarker assays, an indirect measure of exposure. CONCLUSION: As far as the direct measurement of air pollutants is concerned, nicotine and 3-Ethenylpyridine levels seem most suitable because of their specificity. Four specific biological markers of tobacco smoke exposure are available: nicotine, cotinine, thiocyanates, and protein or DNA adducts. Only urinary cotinine assay can be retained as a reliable marker of exposure to tobacco smoke. It has been used as a reference in most epidemiological studies but only reflects tobacco exposure over the preceding 48 hours. The measurement of nicotine and cotinine levels in the appendages of the skin (hair and nails) reflects exposure to tobacco over the previous three months and could become a better reference marker in epidemiological and toxicological studies.