Abstract
Background: Data on the impact of allergic sensitization on asthma and allergic rhinitis among elderly is rare.
Aim: To assess the impact of allergic sensitization on asthma and allergic rhinitis in relation to age.
Methods: A random population sample in ages 22-82 years was examined with structured interview and blood sampling for specific IgE for ten common airborne allergens. Of 1016 invited, 692 (68%) subjects participated in blood sampling. IgE ≥ 0.35 U/ml to the specific allergens was defined as a positive test.
Results: Sensitization to both any allergen and specific allergens decreased with increasing age among subjects with asthma, allergic rhinitis and concomitant condition. Further, the prevalence of allergic sensitization among asthmatics decreased with increasing age of asthma onset, 86% with asthma onset ≤6 y, 56% between 7 and 19 y, 26% with asthma onset ≥20 y. In asthmatics ≥61 y, 22% were sensitized to any allergen, all of which were sensitized to cat, dog or horse. In subjects ≥61 y with allergic rhinitis, 27% were sensitized to any allergen, 20% to pollen, and 18% to animal. When the analysis was stratified for age and adjusted for confounders, sensitization to animal was stronger associated with asthma in ages ≥61y, OR 6.78 (95% CI 2.09-21.99) compared to subjects ≤40y, OR 3.96 (1.41-11.15). An inverse pattern was seen for allergic rhinitis.
Conclusion: Although the overall impact of allergic sensitization on asthma and allergic rhinitis decreased with increasing age, the impact of sensitization to animal remained significant for asthma among elderly. Allergic sensitization has its strongest impact in asthmatics with early onset of asthma.
- © 2014 ERS