INCREASING body mass index (BMI) during childhood may contribute to poorer asthma control and declining lung function, according to findings from the All Age Asthma Cohort (ALLIANCE) study presented at the European Respiratory Society (ERS) Congress.
The results suggest that BMI trajectories beginning early in life may influence both the development and clinical course of paediatric asthma, highlighting a potential window for early preventive intervention.
Previous research has demonstrated that BMI trajectories can influence patterns of lung function during childhood. However, the relationship between longitudinal changes in BMI and the onset and progression of different asthma phenotypes has remained less clear.
To investigate this association researchers at University Hospital Cologne, Germany, and colleagues analysed longitudinal anthropometric, spirometric, and clinical data from 424 children and adolescents enrolled in the ALLIANCE cohort.
Participants had a mean age of 6.24 years, and 33% were female.
Using a latent class mixture model, researchers identified two distinct standardised BMI (zBMI) trajectories. Of the participants, 158 followed a decreasing zBMI trajectory, while 266 demonstrated an increasing zBMI trajectory.
The investigators then examined associations between these trajectories and maternal anthropometric measurements during pregnancy, children’s measurements from birth, inhaled corticosteroid (ICS) dosage, and lung function.
A general linear mixed model was additionally used to assess the longitudinal relationship between zBMI and asthma symptom control, measured using Global Initiative for Asthma (GINA) criteria, as well as lung function assessed by FEV1 and the FEV1/FVC ratio.
Children following an increasing zBMI trajectory differed significantly across several early-life and clinical characteristics.
An increasing zBMI trajectory was associated with higher maternal BMI at the beginning of pregnancy and higher birthweight. Children in this group also experienced an earlier onset of asthma symptoms.
Furthermore, participants with an increasing BMI trajectory required higher doses of ICS at the baseline study visit, suggesting an association between rising BMI and greater treatment requirements.
Longitudinal analyses further demonstrated that increasing zBMI was associated with worsening asthma outcomes.
For each year of life, higher zBMI was associated with a 2.4% increased risk of uncontrolled asthma according to GINA symptom-control criteria.
Higher zBMI was also associated with a lower standardised FEV1/FVC ratio in both males and females indicating poorer airflow relative to lung capacity.
A sex-specific association was additionally observed for FEV1, with higher zBMI linked to lower FEV1 among males.
Together, the findings indicate that BMI trajectories may be relevant not only to the development of asthma symptoms but also to subsequent symptom control and lung function.
The researchers concluded that childhood BMI trajectories may play an important role in determining asthma severity and respiratory health over time.
Identifying children following an increasing BMI trajectory could therefore provide an opportunity for earlier intervention, particularly among those already at risk of developing asthma.
The findings also suggest that monitoring changes in BMI across childhood, rather than relying solely on BMI measured at a single time point, may provide additional insight into the risk of poorer asthma control and lung function decline.
Further research will be needed to determine whether interventions targeting modifiable factors associated with BMI trajectories can improve long-term respiratory outcomes in children with asthma.
Reference
Trojan T et al. Body Mass Index-trajectories in early life are linked to lung function decline and low symptom control in pediatric asthma. Abstract 3397. ERS Congress, 5th-9th September 2026.
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