McGowan Emily C, Bloomberg Gordon R, Gergen Peter J, Visness Cynthia M, Jaffee Katy F, Sandel Megan, O'Connor George, Kattan Meyer, Gern James, Wood Robert A
Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, and the Johns Hopkins Bloomberg School of Public Health, Baltimore, Md.
Division of Allergy, Immunology, and Pulmonary Medicine, Washington University School of Medicine, St Louis, Mo.
J Allergy Clin Immunol. 2015 Jan;135(1):171-8. doi: 10.1016/j.jaci.2014.06.033. Epub 2014 Aug 13.
Previous data suggest that food allergy (FA) might be more common in inner-city children; however, these studies have not collected data on both sensitization and clinical reactivity or early-life exposures.
Children in the Urban Environment and Childhood Asthma birth cohort were followed through age 5 years. Household exposures, diet, clinical history, and physical examinations were assessed yearly; levels of specific IgE to milk, egg, and peanut were measured at 1, 2, 3, and 5 years of age. On the basis of sensitization (IgE ≥0.35 kU/L) and clinical history over the 5-year period, children were classified as having FA or being possibly allergic, sensitized but tolerant, or not allergic/not sensitized.
Five hundred sixteen children were included. Overall, 55.4% were sensitized (milk, 46.7%; egg, 31.0%; and peanut, 20.9%), whereas 9.9% were categorized as having FA (peanut, 6.0%; egg, 4.3%; and milk, 2.7%; 2.5% to >1 food). The remaining children were categorized as possibly allergic (17.0%), sensitized but tolerant (28.5%), and not sensitized (44.6%). Eighteen (3.5%) reported reactions to foods for which IgE levels were not measured. Food-specific IgE levels were similar in children with FA versus sensitized but tolerant children, except for egg, levels of which were higher in patients with FA at ages 1 and 2 years. FA was associated with recurrent wheeze, eczema, aeroallergen sensitization, male sex, breast-feeding, and lower endotoxin exposure in year 1 but not with race/ethnicity, income, tobacco exposure, maternal stress, or early introduction of solid foods.
Even given that this was designed to be a high-risk cohort, the cumulative incidence of FA is extremely high, especially considering the strict definition of FA that was applied and that only 3 common allergens were included.
既往数据表明，食物过敏（FA）在内城区儿童中可能更为常见；然而，这些研究并未收集致敏和临床反应性或早期生活暴露的数据。
对城市环境与儿童哮喘出生队列中的儿童进行随访至5岁。每年评估家庭暴露、饮食、临床病史和体格检查；在1、2、3和5岁时测量针对牛奶、鸡蛋和花生的特异性IgE水平。根据5年期间的致敏情况（IgE≥0.35 kU/L）和临床病史，将儿童分为患有FA、可能过敏、致敏但耐受或未过敏/未致敏。
纳入516名儿童。总体而言，55.4%的儿童致敏（牛奶，46.7%；鸡蛋，31.0%；花生，20.9%），而9.9%的儿童被归类为患有FA（花生，6.0%；鸡蛋，4.3%；牛奶，2.7%；2.5%至超过1种食物）。其余儿童被归类为可能过敏（17.0%）、致敏但耐受（28.5%）和未致敏（44.6%）。18名（3.5%）儿童报告了对未检测IgE水平的食物的反应。FA儿童与致敏但耐受儿童的食物特异性IgE水平相似，但鸡蛋除外，FA患者在1岁和2岁时鸡蛋的IgE水平较高。FA与反复喘息、湿疹、吸入性过敏原致敏、男性、母乳喂养以及第1年较低的内毒素暴露相关，但与种族/民族、收入、烟草暴露、母亲压力或固体食物的早期引入无关。
即使这是一个设计为高风险的队列，但FA的累积发病率极高，尤其是考虑到所应用的FA严格定义且仅纳入了3种常见过敏原。
