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

Background The prevalences of obstructive and restrictive spirometric phenotypes, and their relation to early-life risk factors from childhood to young adulthood remain poorly understood. The aim was to explore these phenotypes and associations with well-known respiratory risk factors across ages and populations in European cohorts. Methods We studied 49 334 participants from 14 population-based cohorts in different age-groups (≤10, >10–15, >15–20, >20–25 years, and overall, 5–25 years). The obstructive phenotype was defined as FEV1/FVC z-score Results The prevalence of obstructive and restrictive phenotypes varied from 3.2–10.9% and 1.8–7.7%, respectively, without clear age trends. A diagnosis of asthma (adjusted odds ratio, aOR=2.55 [95% CI=2.14–3.04]), preterm birth (aOR=1.84 [1.27–2.66]), maternal smoking during pregnancy (aOR=1.16 [1.01–1.35]), and family history of asthma (aOR=1.44 [1.25–1.66]) were associated with a higher prevalence of obstructive, but not restrictive phenotype across ages (5–25 years). A higher current body mass index (BMI) was more often observed in those with the obstructive phenotype but less in those with the restrictive (aOR=1.05 [1.03–1.06] and aOR=0.81 [0.78–0.85], per kg/m2 increase in BMI, respectively). Current smoking was associated with the obstructive phenotype in participants older than 10 years (aOR=1.24 [1.05–1.46]). Conclusion Obstructive and restrictive phenotypes were found to be relatively prevalent during childhood, which supports the early origins concept. Several well-known respiratory risk factors were associated with obstructive phenotype, whereas only low BMI was associated with the restrictive phenotype, suggesting different underlying pathobiology of these two phenotypes.