Fractional exhaled nitric oxide measurements are most closely associated with allergic sensitization in school-age children.
BACKGROUND
Factors affecting fractional exhaled nitric oxide (FeNO) in early childhood are incompletely understood.


OBJECTIVE
To examine the relationships between FeNO and allergic sensitization, total IgE, atopic dermatitis, rhinitis, asthma, and lung function (spirometry) in children.


METHODS
Children at high risk of asthma and other allergic diseases because of parental history were enrolled at birth and followed prospectively. FeNO was measured by an online technique at ages 6 and 8 years. Relationships among FeNO, various atopic characteristics, and asthma were evaluated.


RESULTS
Reproducible FeNO measurements were obtained in 64% (135/210) of 6-year-old and 93% (180/194) of 8-year-old children. There was seasonal variability in FeNO. Children with aeroallergen sensitization at ages 6 and 8 years had increased levels of FeNO compared with those not sensitized (geometric mean; 6 years, 10.9 vs 6.7 parts per billion [ppb], P < .0001; 8 years, 14.6 vs 7.1 ppb, P < .0001). FeNO was higher in children with asthma than in those without asthma at 8 years but not 6 years of age (6 years, 9.2 vs 8.3 ppb, P = .48; 8 years, 11.5 vs 9.2 ppb, P = .03). At 8 years of age, this difference was no longer significant in a multivariate model that included aeroallergen sensitization (P = .33). There were no correlations between FeNO and spirometric indices at 6 or 8 years of age.


CONCLUSIONS
These findings underscore the importance of evaluating allergen sensitization status when FeNO is used as a potential biomarker in the diagnosis and/or monitoring of atopic diseases, particularly asthma.
Jackson
Daniel J
DJ
Department of Pediatrics, University of Wisconsin-Madison, Madison, Wis, USA. djj@medicine.wisc.edu
Virnig
Christine M
CM
Gangnon
Ronald E
RE
Evans
Michael D
MD
Roberg
Kathy A
KA
Anderson
Elizabeth L
EL
Burton
Ryan M
RM
Salazar
Lisa P
LP
DaSilva
Douglas F
DF
Shanovich
Kathleen M
KM
Tisler
Christopher J
CJ
Gern
James E
JE
Lemanske
Robert F
RF
D001249:Asthma / Q000175:diagnosis* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000175:diagnosis* / Q000276:immunology; D045853:Exhalation / Q000276:immunology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000175:diagnosis* / Q000276:immunology; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D007231:Infant, Newborn; D016014:Linear Models; D008297:Male; D009569:Nitric Oxide / Q000032:analysis*; D011446:Prospective Studies; D012220:Rhinitis / Q000175:diagnosis* / Q000276:immunology; D013147:Spirometry
D009569:Nitric Oxide; D007073:Immunoglobulin E