title: Challenges in epidemiologic allergy research.
authors.affiliation: Institute of Environmental Medicine, Karolinska Institute, Stockholm, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Pershagen
mesh_terms: D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D012307:Risk Factors