Elevated exhaled nitric oxide in newborns of atopic mothers precedes respiratory symptoms.
BACKGROUND
Exhaled nitric oxide (NO) is a well-known marker of established airway inflammation in asthma. Its role in the disease process before the onset of respiratory symptoms remains unclear.


OBJECTIVE
To examine whether elevated NO in newborns with clinically naive airways is associated with subsequent respiratory symptoms in infancy.


METHODS
We measured exhaled NO concentration and output after birth and prospectively assessed respiratory symptoms during infancy in a birth cohort of 164 unselected healthy neonates. We examined a possible association between NO and respiratory symptoms using Poisson regression analysis.


RESULTS
In infants of atopic mothers, elevated NO levels after birth were associated with increased risk of subsequent respiratory symptoms (risk ratio [RR], 7.5; 95% confidence interval [CI], 1.7-32.4 for each nl/s increase in NO output; p = 0.007). Similarly, a positive association between NO and symptoms was seen in infants of smoking mothers (RR, 6.6; 95% CI, 2.3-19.3; p = 0.001), with the strongest association in infants whose mothers had both risk factors (RR, 21.8; 95% CI, 5.8-81.3; p < 0.001).


CONCLUSIONS
The interaction of NO with maternal atopy and smoking on subsequent respiratory symptoms is present early in life. Clinically, noninvasive NO measurements in newborns may prove useful as a new means to identify high-risk infants. Future confirmation of a role for NO metabolism in the evolution of respiratory disease may provide an avenue for preventative strategies.
Latzin
Philipp
P
Department of Pediatrics, University of Berne Inselspital, 3010 Bern, Switzerland.
Kuehni
Claudia E
CE
Baldwin
David N
DN
Roiha
Hanna L
HL
Casaulta
Carmen
C
Frey
Urs
U
D001249:Asthma / Q000175:diagnosis* / Q000503:physiopathology; D001944:Breath Tests; D005260:Female; D006801:Humans; D006967:Hypersensitivity; D007223:Infant; D007231:Infant, Newborn / Q000502:physiology*; D009569:Nitric Oxide; D011247:Pregnancy; D011248:Pregnancy Complications; D011446:Prospective Studies; D012044:Regression Analysis; D012307:Risk Factors; D012907:Smoking
D009569:Nitric Oxide