Normal aging contribute to the low prevalence of allergic sensitization among elderly
Published Online: October 5, 2011
Allergic sensitization has been studied in cross-sectional studies and the results are consistent; among adults, the prevalence of allergic sensitization decreases with increasing age. A birth cohort effect has been discussed as a reason for this pattern, i.e., subjects born more recently has been growing up under conditions that may increase the development of allergic sensitization.
In a recent article in The Journal of Allergy and Clinical Immunology (JACI), Warm et al have in a longitudinal setting evaluated the natural process of allergic sensitization among adults. They used data from a random sample of the general population who was examined in 1995 and followed up in 2005. The cohort was interviewed and skin prick testing with ten common allergens was performed. The same methods were used in 1995 and at the follow up. However, at the follow-up in 2005 also specific IgE was measured. The high participation rate, 555 (93% of invited) participated at the follow-up, supports the validity of their results.
The researchers analyzed the prevalence of allergic sensitization, measured as a positive skin prick test or presence of elevated specific IgE, and found a significant association to age. The prevalence was highest in young adults and decreased with increasing age. In analyses of the longitudinal course they revealed a low incidence (5%) and a high remission (32%) of allergic sensitization over the 10 years. Remission was highest among older subjects. Interestingly, in this cohort of adults, they found that having had furred animals at home during childhood was negatively related to specific IgE.
The authors explain that the low incidence and high remission of allergic sensitization in adulthood causes the decreasing prevalence by age. They thus argue that the low prevalence of allergic sensitization among the elderly found in cross-sectional studies is an effect of normal aging and not primarily a birth cohort effect.
The Journal of Allergy and Clinical Immunology (JACI) is the official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.