Incidence of allergic rhinitis in a cohort of young adults from 13-15 years old to 23-25 years old in Castellon (Spain)

Background: The objective of this study was to estimate the incidence of Allergic Rhinitis (AR) in young adults and its risk or protective factors.

Methods: A population-based prospective cohort study was carried out in 2012. The cohort participated in the International Study of Asthma and Allergy in Childhood in Castellon in 1994 and 2002. A telephone survey was conducted using the same questionnaires. A new case of AR was defined as the participants free of the disease in 2002, who self-reported suffering from AR or taking medications for AR in the period 2002-2012.

Results: Of the 1805 schoolchildren in the cohort in 2002, 1435 young adults (23-25 years old) participated (follow-up 79.1%) in 2012; 743 were female and 692 male; their mean age was 24.9±0.6 years. Two hundred new cases of AR occurred in 1259 participants free of the disease with an incidence of 17.3 per 1000 person-years, and the incidence increased from 2002 (RR=1.42; 95% CI 1.15-1.75). The risk factors of AR adjusted by age and gender were sinusitis (RR=1.77; 95% CI 1.16-2.68), atopic dermatitis (RR=1.51; 95% CI 1.11-2.06) and constant exposure to truck traffic (RR=1.88; 95% CI 1.12-3.17). For male participants, the risk factors were asthma, sinusitis and atopic dermatitis, and for females bronchitis was a risk factor and presence of older siblings a protective factor.

Conclusions: An increase in AR incidence was observed. Sinusitis, atopic dermatitis and constant exposure to truck traffic were the risk factors of the AR with some differences by gender.