RATIONALE: There is dramatic increase in incidence of allergic diseases in Asia. Data concerning factors associated with atopic predisposition in children are still limited and contradictory. Genetic predisposition and environmental factors may influence the susceptibility to allergic manifestations.
METHODS: Population-based birth cohort study in Asian population was conducted from July 2015 to May 2017 in Bangkok, Thailand. Data on perinatal and postnatal factors were collected by questionnaires. Diagnosis of allergic diseases was confirmed by allergists. Sensitization was identified by skin test. Oral food challenges were performed for diagnosis of food allergy.
RESULTS: Three hundred and sixty nine mother-children pairs were enrolled, 336 (91%) had follow-up visits until 18 months of age. The cumulative incidence of atopic diseases was 12.5%, including atopic dermatitis (AD), food allergy and chronic urticaria. Exposure to antibiotics before 9 months was associated with atopic diseases; adjusted relative risk (aRR)=2.58(1.22-5.44),p=0.013. Early regular moisturizer used before 2 months decreased risk of atopic diseases; aRR=0.16(0.08-0.34);p=0.001 and AD; aRR=0.06 (0.02-0.16);p=0.001. Delivery mode, parental atopy, parental education, family income, having sibling, exclusive breastfeeding for 4-6 months, having pets, day care attendance and smoke exposure was not significantly associated with atopic diseases in infants.
CONCLUSIONS: Our study identified factors associated with allergic diseases in infants in an Asian birth cohort. Early life exposure to antibiotic increased incidence of allergic diseases while regular moisturizer used before 2 months of age prevented development of allergic disease, especially AD. In contrast to previous studies in western countries, parental atopy was not significantly associated with infant allergic diseases.