Supplementary Material for: Early Introduction of Egg and the Development of Egg Allergy in Children: A Systematic Review and Meta-Analysis

<b><i>Background:</i></b> The timing of the introduction of egg to an infant’s diet is of current interest, as new evidence raises questions regarding the benefit of delaying egg introduction. The objective of this study was to systematically review the existing literature regarding the effect of the early introduction of egg on the development of egg allergy. <b><i>Methods:</i></b> Literature searches were conducted in MEDLINE, EMBASE, and CENTRAL, and trial protocols were searched in Meta Register and OpenGREY. Only randomized controlled trials (RCTs) comparing early (between 3 and 6 months of age) egg introduction to no early introduction were included. The primary outcome was the development of egg allergy. <b><i>Results:</i></b> Of the 416 articles identified and screened, 6 RCTs met the eligibility criteria for data extraction. Allergic outcomes were evaluated in a total of 3,032 participants. A low to moderate level of evidence showed a benefit of the early introduction of egg (relative risk, RR 0.60, 95% CI 0.44–0.82, <i>p</i> = 0.002, mild heterogeneity, <i>I</i>² = 23%). The absolute risk reduction for a population with an incidence of egg allergy of 9.3% was 37 fewer cases (95% CI 17–52) per 1,000 people. Consumption of &lt; 4,000 mg/week of egg protein had a greater preventive effect than a higher dose. <b><i>Conclusion:</i></b> This systematic review and meta-analysis showed an association between the early introduction of egg and a lower risk of egg allergy. Furthermore, the nature and dose of egg protein exposure may play a role. These findings should be addressed in the context of primary studies.

<b><i>研究背景：</i></b> 婴儿辅食中引入鸡蛋的时机当前备受关注，新的研究证据对延迟引入鸡蛋的益处提出了质疑。本研究旨在系统回顾现有关于早期引入鸡蛋对鸡蛋过敏发生风险影响的相关文献。<b><i>研究方法：</i></b> 研究团队在MEDLINE、EMBASE及CENTRAL数据库中开展文献检索，并在Meta Register与OpenGREY数据库中检索试验方案。仅纳入对比早期（3~6月龄）引入鸡蛋与未早期引入鸡蛋的随机对照试验（randomized controlled trial, RCT）。本研究的主要结局指标为鸡蛋过敏的发生情况。<b><i>研究结果：</i></b> 在检索并初筛得到的416篇文献中，共有6项RCT符合数据提取的纳入标准。共计3032名受试者的过敏结局被纳入评估。低至中等质量的证据显示，早期引入鸡蛋可带来获益（相对危险度RR=0.60，95%置信区间CI：0.44~0.82，p=0.002，异质性程度较轻，I²=23%）。在基线鸡蛋过敏发病率为9.3%的人群中，每千人可减少37例发病（95%CI：17~52）。每周摄入鸡蛋蛋白量低于4000mg时，其预防过敏的效果优于更高剂量的摄入。<b><i>研究结论：</i></b> 本项系统评价与荟萃分析结果显示，早期引入鸡蛋与更低的鸡蛋过敏风险存在关联。此外，鸡蛋蛋白的暴露形式与摄入剂量或可发挥调节作用。上述研究结论需结合原始研究进一步探讨与验证。