Risk factors for allergic diseases: a cross-sectional survey of 9,501 Chinese preschool-aged children

Background: Childhood allergic diseases are increasing worldwide with unprecedented complexity and severity, and they cause a major burden on health and healthcare costs. We aimed to identify potential factors, both in isolation and in combination, associated with allergic diseases among preschool-aged children, and to construct a nomogram prediction model based on significant factors. Methods: We cross-sectionally recruited 9,501 preschool-aged children from 30 kindergartens in Beijing and Tangshan. Allergic diseases were ascertained according to the "International Study of Asthma and Allergies in Childhood" questionnaire. Risk for allergic diseases is quantified by odds ratio (OR) with 95% confidence interval (CI). Results: Four factors were identified to be independently, consistently, and significantly associated with the risk for allergic diseases overall and by four clinical manifestations separately, including bedtime (per 1 hour late) (taking asthma/wheezing as an example, OR, 95% CI, P: 1.21, 1.08 to 1.35, 0.001), outdoor activities <= 1.5 h per day (1.45, 1.26 to 1.68, 3.77E-07), family history of allergic diseases (2.23, 1.92 to 2.60, 0.00E+00), and antibiotic use during childhood (3.64, 2.44 to 5.42, 1.66E-10). Further analyses revealed that family history of allergic diseases acted with antibiotic use during childhood in an additive manner. For practical reasons, risk prediction nomogram models were constructed for allergic diseases respectively in Beijing and Tangshan based on significant and conventional factors, and the prediction accuracy was good, with the C-index 69% in Tangshan and 68% in Beijing (both P=0.00E+00). Conclusions: Our findings identified four factors in significant association with the risk for allergic diseases, and in particular family history of allergic diseases and antibiotic use during childhood acted additively.