Longitudinal asthma and allergy study showed that childhood symptoms frequently persisted into adulthood.

AIMS: The prevalence of allergic diseases is high and increasing in many countries. The aim of this study was to describe the prevalence of allergic diseases and changes in clinical expression in a birth cohort followed for three decades. METHODS: We followed Icelandic citizens born in 1987 for allergic diseases when they were 2, 4, 8, 15, 21 and 29 years of age. These were diagnosed using standardised questionnaires, physical examinations and skin-prick tests. RESULTS: Just under half (46%) of the 112 who took part at 29 years of age had one or more allergic diseases, usually mild. Eczema was confirmed in 14% and was highest at the age of 2 years (31%). The prevalence of asthma was 23% and was highest at the age of 4 years (28%). Allergic rhinitis affected 30% at 29 years of age but was not found before the age of 2 years. In addition, 34% had a positive skin-prick test at 29 years of age. CONCLUSION: The results show that 46% of Icelandic adults diagnosed with allergic diseases during childhood still had symptoms at the age of 29, usually mild, developing from eczema in infancy to asthma and allergic rhinitis in adulthood.

A long-term follow-up of allergic diseases in Iceland.

INTRODUCTION: Allergic disorders are an increasing health problem in many countries, in particular among children. We have evaluated the prevalence and manifestations of allergy in a cohort of young Icelanders for more than two decades. Variations in the epidemiology and clinical expression of allergy in different communities may help to identify etiological factors contributing to these disorders. METHODS: A cohort of 179 children has been monitored for allergic manifestations for two decades, at the ages of two, four, eight, and 15 years, and most recently at the age of 21 years involving 120 of the participants. RESULTS: Cumulative prevalences of 40%, 45%, and 29% have been observed, respectively, for rhinoconjunctivitis, eczema, and asthma during the study period. None had developed rhinoconjunctivitis at the age of about 2 years, but the point prevalence gradually increased to 33% at the age of 21 years. Conversely, the prevalence of eczema was 31% at the age of 2 years, but gradually declined to 8% at the age of 21 years. The prevalence of asthma peaked at 28% at the age of 4 years, but declined thereafter and has remained stable at about 13% from the age of eight to 21 years. DISCUSSION: The prevalence of allergic diseases is high in Iceland among children and young individuals. Asthma and atopic eczema are very common in childhood, but decreases with age while the prevalence of rhinoconjunctivitis increases markedly. The very high and increasing prevalence of rhinoconjunctivitis among 15- to 21-year-old individuals is noteworthy.