Spirometric phenotypes from early childhood to young adulthood – A CADSET (Chronic Airway Disease Early Stratification) study

Abstract

Background: Results from longitudinal cohort studies show that the lower the lung function in childhood and adulthood, the higher the risk of later chronic airway disease such as COPD. Yet, reliable data is sparse on the prevalence of different types of lung function impairments in the general population of children and young adults, as well as their major determinants.

Aim: To report age- and sex-specific prevalences and characteristics of spirometric phenotypes from childhood up to young adulthood.

Methods: Lung function data from independent European population-based cohorts involved in the CADSET collaboration were analysed. Pre-bronchodilator FEV1 and FVC data from each cohort were converted into z-scores according to the Global Lung Initiative (GLI) reference system. Overall fit with the GLI spirometry equations was assessed. Airway limitation was defined as a FEV1/FVC z-score < -1.65.

Results: Five cohorts provided spirometry data from 10,842 observations in subjects aged 7 to 25 years. Airway limitation was found in around 6-10% across all ages in the cohorts. No evidence of differences between males and females in different age groups were observed. In unadjusted analyses of all cohorts, we found maternal smoking during pregnancy to be associated with airway limitation (p<0.05).

Conclusion: Analyses of spirometry data from population-based cohorts in Europe show that the prevalence of airflow limitation according to GLI is substantial (6-10%) and quite similar across cohorts and age groups. These results suggest that airflow limitation can develop early in life and that there are rather small changes in prevalence during childhood.