Fractional Exhaled Nitric Oxide (Feno) Is A Marker Of Allergic Inflammation In High Risk 5 Year Old Children

RATIONALE: Fractional exhaled nitric oxide (FeNO) could be useful as a biomarker of lower airway inflammation in young children, but relationships with atopic characteristics are incompletely understood. METHODS: Study subjects were 141 five-year-old children in the Childhood Origins of ASThma (COAST) project, a prospective birth cohort study of children at high risk of developing allergies and/or asthma based on parental histories. Measurements of FeNO were completed using the online technique with the NIOX® system (Aerocrine, AB, Stockholm, Sweden). FeNO was calculated from three maneuvers that were within 2.5 ppb or 10%. Total and specific IgE levels were determined by fluoroenzyme immunoassay (FEIA, Pharmacia), and values > 0.35 kU/L were considered positive. RESULTS: Children with one or more positive RAST results to food or aeroallergens at age 5 had significantly higher FeNO values than children who had negative RAST results ((geometric mean) 7.5 vs 5.6 ppb, p = 0.02). FeNO was significantly greater in girls compared to boys (7.4 vs 6.0 ppb, p=0.05). In addition, FeNO was positively associated with total IgE at age 5 (rs = +0.21, p = 0.01). A history of wheezing was not associated with increased FeNO. CONCLUSIONS: In high-risk preschool aged children, levels of exhaled nitric oxide are significantly associated with total and specific IgE levels, but not with a history of episodic wheezing. We also found evidence of a possible effect of gender on FeNO in early childhood.