Longitudinal prospective population-based birth cohort studies of the natural history of sensitization and allergic diseases from childhood to adulthood are few. The aim of the present prospective study was to investigate the natural course of sensitization and allergic diseases in a random population-based sample of 276 children from a 1-year birth cohort of unselected Danish children followed from birth to 26 years of age.
Questionnaire-based interviews, physical examination, skin prick tests, specific IgE testing, and from 10 years also spirometry, were carried out at 1.5, 5, 10, 15 and 26 years of age. Predefined diagnostic criteria were used.
Follow-up rates were high, 193 (70%) attended the 26-year follow-up. The prevalence of current eczema was stable during childhood; 13% (1.5 yrs.), 9.2% (5 yrs.), 10.8% (10 yrs.), and 9.8% (15 yrs.), and 5.7% at 26 yrs. From birth to 26 years the cumulative prevalence of eczema, food allergy, asthma, and rhinoconjunctivitis was 23.5%, 13.8%, 17%, and 27.9% respectively. More than half of the participants had one or more allergic disease in the period between birth and 26 years of age. The rates of sensitization (S-IgE = 0.35 kU/l) were 8%, 23%, 26%, 32%, and 31% at 1.5, 5, 10, 15, and 26 years of age, respectively. Sensitization to food allergens was most prevalent in early infancy, whereas sensitization to inhalant allergens dominated later on.
The results support the concept of the allergic march. Allergic diseases are not only occurring in childhood but persist into adulthood.