Symptoms of asthma, bronchial responsiveness and atopy in immigrants and emigrants in Europe

Migration studies on asthma may provide information on its environmental ca uses. The European Community Respiratory Health Survey has potential advant ages due to the number of countries involved, standardized collection of in formation, assessment of directionality of migration, and availability of p hysiological data on bronchial responsiveness and atopy. Prevalence rates of symptoms associated with asthma were compared for immig rants, emigrants and nonmigrants living in centres mostly in western Europe . Similar analyses were carried out for bronchial responsiveness (provocati ve concentration causing a 20% fall in forced expiratory volume in one seco nd and slope) and atopy. Medication and use of health services were also ex plored. Overall, 1,678 (8.6%) of 19,516 participants were immigrants in the 18 coun tries participating in the study, of whom 581 were emigrants from one of th e participating countries. Rates of asthma symptoms were higher in immigran ts (odds ratio (OR): 1.21, 95% confidence interval (CI): 1.00-1.51) and emi grants (OR: 1.31, 95% CI: 0.96-1.51) compared to nonmigrants after controll ing for area, sex, age and smoking status. However, bronchial responsivenes s and atopy were equally distributed between immigrants, emigrants and nonm igrants. Use of health services was observed to be similar in migrants and nonmigrants with asthma. In the European Community Respiratory Health Survey, migrants reported more asthma symptoms, but had similar bronchial responsiveness, atopy, and use of health services when compared with the nonmigrant population.