Characterization of Asthma by Age of Onset: A Multi-Database Cohort Study

Asthma can occur at any age but the differences in patient characteristics between childhood-, adult-, and late-onset asthma are not well understood.

To investigate differences in patients' characteristics by age at asthma onset.

From 5 European electronic databases, we created a cohort encompassing adult patients with doctor-diagnosed asthma in 2008 to 2013. Patients were categorized based on their age at asthma onset: childhood-onset (age at onset < 18 y), adult-onset (age at onset 18-40 y), and late-onset asthma (age at onset ≥ 40 y). Comorbidities were assessed at study entry. For each characteristic and comorbidity, odds ratios and age- and sex-adjusted odds ratios (OR_adj) comparing asthma-onset categories were estimated per database and combined in a meta-analysis using a random effect model.

In total, 586,436 adult asthma patients were included, 81,691 had childhood-onset, 218,184 adult-onset, and 286,561 late-onset asthma. Overall, 7.3% had severe asthma. Subjects with adult-onset compared with childhood-asthma had higher risks for overweight/obesity (OR_adj 1.4; 95% CI 1.1-1.8) and lower risks for atopic disorders (OR_adj 0.8; 95% CI 0.7-0.95). Patients with late-onset compared with adult-onset asthma had higher risks for nasal polyposis (OR_adj 1.8; 95% CI 1.2-2.6), overweight/obesity (OR_adj 1.3; 95% CI 1.2-1.4), gastroesophageal reflux disease (OR_adj 1.4; 95% CI 1.2-1.7), and diabetes (OR_adj 2.3; 95% CI 1.8-2.9). A significant association between late-onset asthma and uncontrolled asthma was observed (OR_adj 2.8; 95% CI 1.7-4.5).

This international study demonstrates clear differences in comorbidities between childhood-, adult-, and late-onset asthma phenotypes in adults. Furthermore, patients with late-onset asthma had more frequent uncontrolled asthma.