Exhaled nitric oxide during infancy as a risk factor for asthma and airway hyperreactivity

Area of Science:

• Pediatric Allergy and Immunology
• Respiratory Medicine
• Clinical Pediatrics

Background:

• Childhood asthma presents with elevated exhaled nitric oxide (eNO), reduced lung function, and increased airway reactivity.
• The developmental timing of these airway phenotypes in relation to asthma onset is not well understood.

Purpose of the Study:

• To investigate if infant eNO, lung function, airway reactivity, and immune markers predict asthma development by age 5.
• To identify early risk factors for asthma and its associated airway characteristics in high-risk infants.

Main Methods:

• Longitudinal study of 116 infants with eczema, assessed before wheezing onset.
• Measurements included eNO, spirometry, airway reactivity, and allergen sensitization at baseline and age 5 (90 participants completed follow-up).

Main Results:

• Increased infant eNO correlated with higher asthma risk (p=0.037) and airway reactivity (p=0.015) at age 5.
• Asthmatic children showed a greater increase in eNO from infancy to age 5 (p=0.002).
• Egg sensitization in infancy predicted asthma risk (p=0.020), elevated eNO (p=0.002), and reduced forced expiratory flows (p=0.029) at age 5.

Conclusions:

• Infant eNO is a potential early indicator of subsequent asthma risk and airway characteristics in high-risk children.
• Early allergen sensitization, specifically to egg, is associated with later asthma development and altered lung function.