Methods: Data from the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS) prospective cohort was assessed to determine the association between the frequency of URIs in the 1styear and subsequent development of allergic sensitization and asthma. CCAAPS is a high-risk birth cohort of one or more confirmed allergic parents. Early sensitization was defined as at least one positive skin prick test (SPT+) from ages1-3, and late sensitization as negative SPTs during 1-3yrs but positive at 7y. High frequency of URI was defined as >6 infections by age 1.
Results: Among CCAAPS children (n= 710), 59% and 10% had early and late sensitization, respectively. There were 96% children with >6 URI during their first year. A high number of URI was significantly associated with almost a two fold increased risk for early sensitization to ragweed, after adjustment for pets, breastfeeding, daycare and antibiotic use (aOR=1.8, 95%CI 1.01-3.1, p=0.046). No association was found between high number of URI and late sensitization to any aeroallergen. Early aeroallergen sensitization (aOR=2.7, 95%CI 1.5-4.7, p=0.001) and high number of URI (aOR 2.33, 95%CI 1.4-3.9, p=0.002) were associated with asthma at 7yrs.
Conclusions: These data demonstrate that a high number of 1st year URI increases the risk for early ragweed sensitization and asthma at 7y. Future studies may want to focus on the mechanistic role of high number of URI, ragweed sensitization early in life and asthma risk.