We have studied asthma and allergic rhinitis prevalence in Swedish conscripts born 1973-1977 according to the military service conscription register in relation to the socio-economic status and country of birth of the conscripts and their parents, and age when granted residency in Sweden. There was an increase in prevalence of asthma and allergic rhinitis over time in all groups irrespective of country of birth or ethnic origin. Conscripts who themselves were born in Africa, Asia, Latin America and the Mediterranean had a significantly lower risk for asthma and allergic rhinitis than Swedish-born conscripts. The risk of atopic disorder among the foreign-born conscripts increased with time of residency in Sweden. Conscripts with mothers from Latin America, Asia and Africa were identified as having the highest risk for atopic disorder among Swedish-born conscripts with high socio-economic status; the adjusted risk ratio (RR) for asthma was 2.6 (95% CI 1.7-4.0) and that for allergic rhinitis was 2.0 (1.5-2.6). The conscripts with mothers from the Mediterranean had the lowest risk for atopic disorders of the Swedish-born conscripts with low socio-economic status; the RR for asthma was 0.43 (0.34-0.56) and that for allergic rhinitis was 0.84 (0.76-0.93). This study demonstrates that factors related to migration and ethnicity are important determinants of atopic disorder among Swedish conscripts.
PURPOSE: To classify a cohort of 62 patients with vernal keratoconjunctivitis (VKC) in immunologic, functional, and epidemiological terms. METHODS: A retrospective chart review was conducted to establish the patients' ethnic origin and to ascertain the results of standard in vitro and in vivo testing for atopic allergy. The latter data were compared with tear Phadiatop, an allergy screening test, in 31 subjects. Further subgroup analyses included methacholine bronchial provocations, serum screening for chlamydial antibodies and epidemiological calculations of the observed prevalence of VKC in the Stockholm area in 1994. RESULTS: Thirty-seven subjects (59.7%) were sensitised to common allergens. No additional allergic subjects were diagnosed with the tear Phadiatop test. The serology for ocular chlamydial disease was negative. Only 6 out of 17 subjects displayed bronchial reactivity to methacholine of whom 4 had a history of asthma. VKC was clearly more common in individuals with an Asian and African origin. CONCLUSIONS: Sensitivity to allergens is a strong determinant for the disease but in a large proportion of the subjects this immunologic abnormality is absent. The varying prevalence of the condition in different ethnic groups indicates a genetic predisposing factor.