Results
A four-cluster solution was determined to reliably represent the data, resulting in distinct phenotypes described as: (1) troublesome, late-onset, non-atopic asthma with smoking (n =458, 24.2%); 2) female-dominated early adult-onset asthma (n =545, 28.7%); 3) adult-onset asthma with high inflammation (n =358, 18.9%); and 4) early-onset, mild, atopic asthma (n =534, 28.2%). The phenotypes also differed with respect to demographics, risk factors, asthma triggers, pulmonary function, symptom profiles, and markers of inflammation. Current asthma was more common in phenotypes with later age of asthma onset than phenotypes with early onset.