Associations of atopy and asthma during aging of an adult population over a 20-year follow-up.

OBJECTIVE: Atopy is associated with asthma, but cross-sectional studies suggest this association may be weaker in older adults. It remains unclear if atopy predicts asthma later in adult life. We aimed to investigate whether atopy in young adults predicted asthma 20 years later and to quantify the contemporaneous relationship of atopy and asthma as adults age.

METHODS: Participants of the European Community Respiratory Health Survey (ECRHS) in Melbourne aged 20-44 years were followed for 20 years and completed questionnaires, skin prick tests (SPT) and allergen specific immunoglobulin E measurement at a baseline and two subsequent surveys. Using logistic regression and generalized estimating equations, we tested if atopy at baseline predicted current asthma later in life and estimated the association between current atopy measured at each survey and current asthma, while adjusting for potential confounders.

RESULTS: The analysis included 220 participants: 50.9% male. Mean (SD) age at baseline was 35.7 (5.7) years. Asthma and atopy prevalence remained stable over 20 years. Baseline atopy (SPT) was associated with current asthma (OR 9.74, 95%CI 4.22, 22.5) over 20 years, and current atopy (SPT) with concurrent asthma (3.12; 1.70, 5.74).

CONCLUSIONS: Atopy remains strongly associated with current asthma in 40 to 64 year-old adults, both prospectively and contemporaneously, but the prospective association is stronger.