Symptoms of Asthma, Bronchial Responsiveness and Atopy in Immigrants and Emigrants in Europe
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Copyright #ERS Journals Ltd 2001 Eur Respir J 2001; 18: 459–465 European Respiratory Journal Printed in UK – all rights reserved ISSN 0903-1936 Symptoms of asthma, bronchial responsiveness and atopy in immigrants and emigrants in Europe A. Tobias*,#, J.B. Soriano*,}, S. Chinnz, J.M. Anto*,§, J. Sunyer*, P. Burneyz, for the European Community Respiratory Health Survey Symptoms of asthma, bronchial responsiveness and atopy in immigrants and emigrants *Respiratory and Environmental Health Research Unit, IMIM, Barcelona, in Europe. A. Tobias, J.B. Soriano, S. Chinn, J.M. Anto, J. Sunyer, P. Burney, for the # European Community Respiratory Health Survey. #ERS Journals Ltd 2001. Spain, Dept of Clinical Epidemiology ABSTRACT: Migration studies on asthma may provide information on its environ- and Public Health, Hospital de la Santa Creu i Sant Pau, Barcelona, mental causes. The European Community Respiratory Health Survey has potential Spain, }Worldwide Epidemiology, advantages due to the number of countries involved, standardized collection of inform- GlaxoSmithKline Rz and D, Greenford, ation, assessment of directionality of migration, and availability of physiological data Middlesex, UK, Dept of Public on bronchial responsiveness and atopy. Health Sciences, Guy9s, King9s and St. Prevalence rates of symptoms associated with asthma were compared for immi- Thomas9 School of Medicine, Guy9s § grants, emigrants and nonmigrants living in centres mostly in western Europe. Similar Hospital, London, UK and Dept of analyses were carried out for bronchial responsiveness (provocative concentration Experimental and Health Sciences, causing a 20% fall in forced expiratory volume in one second and slope) and atopy. Universitat Pompeu Fabra (UPF), Medication and use of health services were also explored. Barcelona, Spain. Overall, 1,678 (8.6%) of 19,516 participants were immigrants in the 18 countries Correspondence: P. Burney, Dept of participating in the study, of whom 581 were emigrants from one of the participating Public Health Sciences, Kings College, countries. Rates of asthma symptoms were higher in immigrants (odds ratio (OR): 1.21, 5th floor Capital House, 42 Weston 95% confidence interval (CI): 1.00–1.51) and emigrants (OR: 1.31, 95% CI: 0.96–1.51) Street, London SE1 3QD, UK. compared to nonmigrants after controlling for area, sex, age and smoking status. Fax: 44 20784 6605 However, bronchial responsiveness and atopy were equally distributed between immigrants, emigrants and nonmigrants. Use of health services was observed to be Keywords: Asthma similar in migrants and nonmigrants with asthma. atopy bronchial responsiveness In the European Community Respiratory Health Survey, migrants reported more European Community Respiratory asthma symptoms, but had similar bronchial responsiveness, atopy, and use of health Health Survey services when compared with the nonmigrant population. healthcare Eur Respir J 2001; 18: 459–465. migration Received: March 20 2000 Accepted after revision May 14 2001 Migrants may have a greater susceptibility to asthma Europe and elsewhere [5–7]. To study the effects of [1]. Variations in the prevalence of disease and increased migration on asthma, the ECRHS has potential rates associated with time, migration and changing advantages: data from 14 European and four other lifestyle highlight the importance of environmental countries, standardized information including direc- agents in the induction of the disease [2]. Compared tion of migration, and physiological data on atopy with studies of cancer and cardiovascular disease, and bronchial responsiveness. international migrant studies of asthma are scarce and By means of a cross-sectional analysis of the very localized, tending to compare immigrants only ECRHS, the authors have compared prevalence with the host populations. Immigrants may suffer rates of asthma symptoms, bronchial responsiveness, from psychological changes including somatization atopy and use of health services by those with asthma due to post-traumatic stress disorder and other in first-generation immigrants and emigrants, and anxiety disorders [3]. As with the unemployed [4], nonmigrants. migrants might lack access to medical care, as well as being more susceptible to respiratory and other Methods conditions. The European Community Respiratory Health Study design and sample Survey (ECRHS) has previously provided informa- tion on the distribution of asthma and asthma-related The study design, methodology and objectives of phenotypes in the 20–44-yr-old population within the ECRHS have been described elsewhere [5]. Briefly, 460 A. TOBIAS ET AL. the ECRHS was conducted in 38 areas of 18 countries Pharmacia CAP method (Pharmacia Diagnostics, from 1991–1993. A random sample of 3,000 males and Uppsala, Sweden) to any of the following allergens: females aged 20–44 yrs from each of the participating Dermatophagoides pteronyssinus, timothy grass, cat, areas was contacted and requested to complete a Cladosporium, or a local allergen. The local allergen short screening questionnaire on respiratory symp- was birch for northern Europe, Parietaria for toms. Subsequently, a 20% random sample (n=19,516) southern Europe and ragweed for the USA, New of the source population was asked to complete a long Zealand and Australia. questionnaire, provide blood samples, undergo skin and forced spirometric tests, and have bronchial responsiveness measured through a methacholine Medication and use of health services challenge test [7]. Use of respiratory medications during the last year was estimated for inhaled, oral and other medicines. Migration and social data Inhaled medicines included b2-agonists, nonspecific b-agonists, antimuscarinics, steroids, compound bronch- Information on country of birth and country of odilators and other inhalers. Oral medicines included residence was self-reported by participants. Immi- b2-agonists, nonspecific b-agonists, antimuscarinic grants were defined as those subjects who were not drugs, methylxanthines, steroids, antihistamines, and born in their current country of residence. A sub- bronchodilators. Finally, other respiratory medica- sample of them were also considered to be emigrants, tions included vaccines, injections, suppositories, and as they were born in one of the participating countries. other remedies. Participants were also asked if medi- Others were considered to be nonmigrants. Social cation was prescribed by a doctor, and the frequency class was defined as manual, nonmanual and other of taking medication, namely every day or only for (including unemployed and housewives) as presented attacks of breathlessness. The use of health services elsewhere [8]. for any respiratory problem, frequency of medication Countries were stratified into zones according to and the type of medical practitioner last contacted whether they had a high, medium or low prevalence were recorded. All analyses on the use of health care of asthma among nonmigrants. The groups were as services focused only on subjects reporting symptoms follows: high: Australia, France, New Zealand, UK, associated with asthma. USA; Medium: Denmark, Ireland, Italy, Sweden, Switzerland; low: Belgium, Germany, Iceland, Nether- lands, Norway, Spain. India and Estonia had virtually Statistical analysis no migrants and were excluded from these analyses. The statistical analysis was done using Stata (StataCorp., College Station, TX, USA) [10]. The Symptoms questionnaire, respiratory function and Chi-squared test was used in the univariate analysis. immunological measurements Multinomial logistic regression [11] was applied to obtain adjusted odds ratios (OR) and their 95% Any individual was considered symptomatic of confidence intervals (CI) by country of residence. asthma if he/she answered yes to any of the following Regression models were adjusted for sex, age (cate- questions of the long questionnaire: "Have you been gorized into five groups, 20–24, 25–29, 30–34, 35–39 woken by an attack of shortness of breath in the last and 40–45 yrs), social class and smoking status. 12 months?", "Have you had an attack of asthma Random effects meta-analysis was used to pool the during the last 12 months?",or"Are you currently results over countries and test for heterogeneity [12]. taking medicines for asthma?". For the assessment of smoking status, participants were asked whether they had smoked at least one cigarette a day, one cigar a Results week for 1 yr or 360 g tobacco in a lifetime [9]. The subjects were categorized into three groups: non- Migration rates smokers, exsmokers and current smokers. Bronchial responsiveness was defined as a pro- There were 1,678 immigrants in the present study, vocative concentration causing a 20% fall in forced constituting 8.6% of the ECRHS study population. expiratory volume in one second (FEV1) (PD20) from Overall, 581 (3.0%) were born in one of the par- the largest postdiluent volume during methacholine ticipating countries, therefore being considered emi- challenge with an estimated cumulative dose of grants from these countries. 5.1 mmol methacholine [7]. Because many participants Migration rates varied widely between countries, will have censored data on bronchial responsiveness the centres of the USA (27.9%), Switzerland (22.4%) as measured by PD20, analysis was also carried out by and Australia (20.5%) had the highest rates of calculating the slope, or regression coefficient of immigrants observed, while those of Italy (1.3%), percentage decline in FEV1 with log dose [7]. Spain (2.0%) and Iceland