Infants were invited to participate at age 18 months in a health examination conducted by a pediatrician. Allergic rhinitis was defined as the presence of rhinitis symptoms (runny nose, blocked nose, sneezing in the absence of a cold) combined with biological atopy (elevated total immunoglobulin E [IgE], specific IgE, or eosinophilia) and nonallergic rhinitis (NAR) as symptoms without biological atopy