Perennial allergen-specific immunoglobulin E levels among inner-city elderly asthmatics

The role of allergen sensitization has been well established among children and young adults with asthma. Some studies have suggested that allergens play a less important role among older patients with asthma. However, whether older asthmatics have a lower prevalence of allergen sensitization than younger adults remains controversial. The aim of this study was to access the prevalence of sensitization to indoor allergens in older compared to younger inner-city adults with persistent asthma.

The authors used data collected as part of a cohort study of inner-city adults with persistent asthma. Sensitization to indoor allergens (specifically Dermatophagoides pteronyssinus, D. farinae, cat, mouse, Aspergillus fumigates, Alternaria, German and American cockroaches) was evaluated by specific immunoglobulin E (IgE) antibodies measured from peripheral blood. Univariate and multiple regression analyses were used to compare ratios of sensitization according to age (≤ 35, 36-59, ≥ 60 years of age).

Of the 245 patients in the study, 19% were over the age of 60 years. Overall 73%, 61%, and 41% of patients ≤ 35, 36-59, and ≥ 60 years old, respectively were sensitized to at least one indoor allergen (p = .01). Multivariate analysis showed that patients ≥ 60 years of age were significantly less likely to be sensitized (odds ratio 0.32, 95% confidence interval 0.11 to 0.89) compared to younger adults after controlling for potential confounders.

Allergen sensitization is less common in older patients with persistent asthma. However, sensitization to any indoor allergen is relatively frequent in the elderly. Physicians should consider routinely accessing exposure and sensitization to these allergens as part of the evaluation of older inner-city patients with persistent asthma.