Development of asthma in a Swedish birth cohort up to the age of 32-34 years

Background: Asthma in adulthood could be programmed in early life. However, the number of cohort studies following the development of asthma from childhood up to adulthood is so far limited and the findings have been contradictory. Objective: To evaluate the development of asthma over time in a cohort born in the mid 1970-ies. Material & Methods: A population-based, non-selected birth cohort comprising 1,701 consecutively born children at a University Hospital in Southeast Sweden. At the age of 6–7 and 10–11 years of age an asthma diagnosis was confirmed by parental questionnaires, telephone check-ups and the review of available medical records. Information on dispensed asthma medication (inhaled corticosteroids and/or leucotriene antagonists) at the ages of 32-34 years was collected from the Swedish Prescribed Drug Register after linkage of data at an individual level. Results: In all, 1,661 individuals (97.6%) of the original birth cohort could be linked to the Swedish Prescribed Drug Register and 48 individuals were diagnosed with asthma at the two follow-ups in childhood. At the age of 32-34 years, 60 individuals were dispensed inhaled corticosteroids or leucotriene antagonists. Out of those, 49 individuals had not been diagnosed with asthma at the check-ups during childhood. Conclusion: The majority of the individuals with asthma in childhood had not been dispensed asthma medication in adulthood. The findings suggest that a major part of the individuals with asthma medication at the age of 32-34 years had developed asthma during or after adolescence.