Supplementary Material for: Food Allergy in Ghanaian Schoolchildren: Data on Sensitization and Reported Food Allergy

Background: Epidemiological data on food allergy are scarce in African countries. We studied the prevalence of food sensitization in Ghanaian schoolchildren. Methods: Children (5–16 years; n = 1,714) from 9 Ghanaian schools were given parental consent to participate in the study. Adverse reactions and food consumption were determined by a questionnaire and atopy by skin prick testing (SPT) to peanut and 6 fruits. Subjects with positive SPTs were considered cases (n = 43) and matched with at least 1 control (n = 84), using age, sex, and school as matching criteria. Serum samples from case-control sets were analyzed for specific IgE (sIgE) to foods that elicited a positive SPT response in cases. Results: Overall, 11% of 1,407 children reported adverse reactions to foods, and 5% of 1,431 children showed a positive SPT reaction mostly directed against peanut and pineapple (both 2%). Although there was a positive association between adverse reactions and SPT responses to any food allergen in the urban children (adjusted OR = 3.6, 95% CI 1.2–10.8), most of the reported adverse reactions were not in children showing an SPT reaction to the specific food item. sIgE sensitization was very variable for the different foods, ranging from 0 to 100% in cases, and from 0 to 25% among controls. High IgE levels for a food item significantly increased the risk of SPT positivity to any food item in the urban, but not in the rural, schoolchildren. Conclusions: Specific foods were identified to be allergenic in Ghana. We show a good association between SPT and sIgE in urban, but not in rural, schoolchildren. However, there was no clear association between reported adverse reactions to food and SPT or sIgE.

研究背景：非洲国家关于食物过敏的流行病学数据较为匮乏。本研究针对加纳学龄儿童的食物致敏流行率展开调查。
研究方法：本研究纳入加纳9所学校的5~16岁学龄儿童共1714名，所有受试者均获得家长知情同意后参与研究。通过问卷调查收集受试者的食物不良反应与食物摄入情况，采用皮肤点刺试验（skin prick testing, SPT）检测受试者的特应性状态，检测变应原包括花生及6种水果。将皮肤点刺试验结果呈阳性的受试者设为病例组（n=43），并以年龄、性别、学校作为匹配标准，为每个病例匹配至少1名对照（n=84）。采集病例-对照配对样本的血清，检测病例组中皮肤点刺试验呈阳性的对应食物的特异性IgE（specific IgE, sIgE）水平。
研究结果：总体而言，1407名受访儿童中有11%报告过食物不良反应，1431名儿童中5%的皮肤点刺试验结果呈阳性，其中主要针对花生和菠萝的阳性反应各占2%。尽管在城市学龄儿童中，食物不良反应与任意食物变应原的皮肤点刺试验阳性结果呈正相关（校正优势比=3.6，95%置信区间1.2~10.8），但多数报告的食物不良反应并未出现在对应食物皮肤点刺试验阳性的儿童中。不同食物的特异性IgE致敏率差异极大，病例组中该范围为0~100%，对照组中为0~25%。对于城市学龄儿童，某一食物的高IgE水平会显著增加其任意食物皮肤点刺试验阳性的风险，但这一关联在农村学龄儿童中未观察到。
研究结论：本研究明确了加纳境内具有致敏性的特定食物。结果显示，城市学龄儿童的皮肤点刺试验结果与特异性IgE水平存在良好的相关性，但这一相关性在农村学龄儿童中未体现。不过，报告的食物不良反应与皮肤点刺试验或特异性IgE水平之间并未发现明确关联。