Characteristics of the case control study population.

†p-values are from the Wilcoxon test and are provided for quantitative variables.*Adjusted for income (using 5 categories shown in table) and race via logistic regression.aAtopy defined as presence of any allergen-specific IgE at a level >35 kIU/L.† p值来自Wilcoxon秩和检验（Wilcoxon test），仅针对定量变量提供该检验的p值。 * 采用logistic回归（logistic regression）校正收入（采用表格中列明的5个收入分类）与种族因素。 a 特应性（atopy）定义为任意一种过敏原特异性IgE（allergen-specific IgE）水平超过35 kIU/L的情况。