Relationship between FEV₁/FVC and age in children with asthma.

Area of Science:

• Pediatric pulmonology
• Respiratory physiology
• Asthma research

Background:

• The typical pattern of forced expiratory volume in the first second (FEV₁)/forced vital capacity (FVC) shows a decrease through childhood, a temporary increase in early adolescence, and a subsequent decline.
• The physiological mechanisms driving the temporary increase in FEV₁/FVC during early adolescence are not fully understood.
• Investigating this pattern in children with persistent asthma is crucial for understanding asthma's impact on lung function development.

Purpose of the Study:

• To determine if the characteristic "Shepherd's Hook" pattern of FEV₁/FVC is present in children with persistent asthma.
• To compare the FEV₁/FVC trajectory in asthmatic children to that of healthy children.
• To assess the influence of obesity on the FEV₁/FVC pattern in children with asthma.

Main Methods:

• Retrospective analysis of pulmonary function tests from 1793 children aged 5-18 with persistent asthma.
• Data collected over a 5-year period at a single center.
• Analysis included comparisons with healthy children and assessment of the impact of obesity.

Main Results:

• Children with persistent asthma exhibited lower FEV₁/FVC ratios compared to healthy children across all ages.
• Despite lower ratios, the "Shepherd's Hook" pattern (increase in early adolescence) was preserved in asthmatic children.
• Obese children with asthma also showed the preserved pattern, albeit with consistently lower FEV₁/FVC values.

Conclusions:

• The "Shepherd's Hook" pattern of FEV₁/FVC is maintained in children with persistent asthma, indicating preserved relative lung growth dynamics.
• Asthma is associated with lower FEV₁/FVC ratios throughout childhood and adolescence compared to healthy peers.
• Obesity does not alter the fundamental pattern of FEV₁/FVC development in children with asthma, but exacerbates the reduction in ratio.