Development of atopic march and co-occurrence of allergic diseases
One-third of the subjects developed at least two types of atopic manifestations at the age of 30 months. This included 25% who developed two types of atopic manifestations (AD+FA, AD+rhinitis, AD+wheezing, FA+rhinitis, FA+wheezing, wheezing+rhinitis), 5% who developed three types of atopic manifestations (AD+wheezing+rhinitis, AD+FA+wheezing, AD+FA+rhinitis), and less than 1 percent (0.9%) who developed all 4 atopic manifestations (AD+FA+wheezing+rhinitis). Sixty percent of subjects with AD and 85% of subjects with FA developed other atopic diseases. Only 9% of the subjects with wheezing and 9% of subjects with rhinitis had other preceeding atopic phenotypes, either AD or FA. These numbers are demonstrated in Figure 1A.
Besides, our cohort found a strong association between allergic diseases. Subjects with FA had an increased risk of having AD with a hazard ratio (HR) of 6.5 (95%CI, 3.2-13.06; p<0.0001 ) while subjects with AD also had 8.5 folds increased risk of having FA; HR=8.51 (95%CI, 3.52-20.56; p<0.0001 ). Having rhinitis before 12 months of age associated with having FA, with HR of 5.53 (95%CI, 1.01-30.46; p=0.049 ). Allergic rhinitis also significantly associated with ever-wheezing with OR of 3.56 (95%CI, 1.01-12.56; p=0.049 ).