Cumulative incidence of allergic diseases
Of the 369 mother-children pairs recruited in our cohort, 279 (75.6%) has completed data collection and follow-up until 30 months of age. Demographic data is shown in Table 1. Fifty-five percent of the infants are male. Most of the participants has no family history of atopic diseases (74.2%). Forty percent of infants were delivered by cesarean section. Forty-one percent of the infants were exclusively breastfed for at least four months.
The cumulative incidence of allergic diseases (Figure 1A) was 46.2 %, including AD (13.9%, N=39), FA (7.2%,N=20), ever wheezing (24%,N=67), and chronic rhinitis (18.6% N=52). If asthma was counted instead of ever wheezing and AR was counted instead of chronic rhinitis, the cumulative incidence of allergic diseases was 17.2 %; asthma (0.7%,N=2), AR (6.1%,N=17). AD and FA were the most prevalent allergic diseases during the first year of life. Most of the cases with AD and FA were outgrown overtime. Meanwhile, the prevalence of wheezing and rhinitis subsequently increased. The point prevalence of allergic diseases from birth up to 30 months is shown in Figure 1B.
Of 39 subjects with AD, mild AD was the most observed (74.4%,N=29) followed by moderate AD (23.1%,N=9) and severe AD (2.5%,N=1). Of 20 subjects with FA, 13 subjects (65.0%) had IgE-mediated reactions. Five subjects (25.0%) had non-IgE mediated reactions, including three subjects with allergic proctocolitis and two with FPIES. Another two subjects (10.0%) with mixed-IgE mediated reactions, eczema was flared after oral food challenge to cow’s milk. Hen’s egg was the most common food allergen (30.0%,N=6), followed by cow’s milk (25.0%,N=5), wheat (20.0%,N=4), shrimp (10.0%,N=2), banana (10.0%,N=2) and fish (5.0%,N=1). In all subjects with ever-wheezing (N=67), most had wheezing for only one time (65.7%,N=44). Twenty-two percent of subjects (N=15) met the definition of recurrent wheezing. Asthma was diagnosed only in two subjects (0.7% of all population subjects). For subjects with rhinitis (N=52), the symptoms started between age 1-2 years old in most cases. Interestingly, 9.6% (N=5) of subjects started to have rhinitis symptoms before one year of age. Seventeen subjects (6.1% of all study population) were fitted with the criteria of AR in our study.