Demographic, risk factors and asthma triggers in derived
phenotypes
Cluster 1 had the highest average age at asthma onset 35, while Cluster
4 had the youngest average age at asthma onset 13 (Table 1).Cluster 1 had the highest average calendar age (65 and the highest
average BMI (28.5) than the other clusters. While it had a lower
urbanization rate (38.9%) than the other clusters, the proportion of
smokers and average pack-year history was the highest. Cluster 1 also
had the highest proportion of individuals exposed to smoking at home and
at work than other clusters (Table 1 and Figure 1:A and
B ). On the other hand, Cluster 2 had the second youngest average age at
asthma onset, was the most female-dominated cluster, the second least
urbanized, highest proportion of never smokers. In this cluster, the
subjects had experienced more household mould, plastic-carpet or water
damage, the highest rate of exertion-induced respiratory symptoms, and
the highest rate of infection-triggered asthma symptoms than other
clusters (Figure 1: A and B ). Cluster 3 had the second oldest
age at asthma onset and had a higher proportion of males than other
clusters (Figure 1 and Figure 2 ). Cluster 4 had the
youngest average age at asthma onset, had the lowest average calendar
age and BMI, more equally distributed between men and women, most
urbanized, lowest pack-years of smoking, lowest rates of smoking
exposure at home and at work (29.8%), and the lowest rates of exercise
and infection as asthma triggers (Table 1 and Figure 1:
A ).