RHINE I was initially recruited as part of the European Community Respiratory Health Survey (ECRHS) I stage I. In ECRHS I stage I, a postal questionnaire was administered to a large population sample of approximately 3000 participants in each centre, followed up by a clinical stage (ECRHS I stage II) of subsamples of the same population. The ECRHS I stage I for the seven centres in RHINE is in the following labelled “RHINE I”. The ECRHS I study was conducted in 1990 to 1994 in order to estimate the variation in the prevalence of asthma and allergy in young adults in Europe and other parts of the world. Second aim was to estimate variations in exposure to risk factors for asthma: to measure their association with asthma and to estimate the variation in treatment practice for asthma in the international community. Total number of participants was 21,802 (response rate 83.7%).