Background: Dietary behaviours are among the key modifiable risk factors for non-communicable diseases. Importantly, dietary behaviours vary substantially between groups and individuals with different socioeconomic positions, with more disadvantaged groups and individuals being exposed to more dietary risk factors. The goal of this review is to summarize the existing research on and identify equity effects of dietary nudging interventions. Methods: Systematic review of nudging interventions conducted in a field setting that report an observable indicator of dietary behaviour, include a control group, and report effect sizes stratified by social inequality as outlined in the PROGRESS-Plus framework. Two databases (scopus, Pubmed) were searched (last search June 2021), and 18 articles with 19 studies (k=46 equity comparisons) were included. Risk of bias was assessed using the ROBINS-I tool. Given their heterogeneity, both, with regard to dimensions of equity and study outcomes, studies were summarized in a meta-synthesis. Results: The majority of equity comparisons (38 out of 46) were available for cognitive nudges. Most of these (22 out of 38 comparisons) found that cognitive nudges worked equally well in more and less disadvantaged populations; however, in 12 out of the 38 comparisons, they favored those who were less disadvantaged. Two out of foud comparisons on behavioural nudges favoured more disadvantaged persons. Conclusions: The differential effects of dietary nudging interventions found in this review can contribute to increases in health inequalities. At the same time, a substantial number of interventions found no equity effects, suggesting that further moderating variables might be responsible for facilitating or buffering equity effects. Importantly, despite these interesting findings, this review clearly shows that more research on nudging interventions and health equity is dearly needed. Future interventions should report effect sizes stratified by any indicator of social inequality.

中文翻译：

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饮食轻推田间试验的公平效应：系统评价和综合综合

背景：饮食行为是非传染性疾病的关键可改变风险因素之一。重要的是，具有不同社会经济地位的群体和个人之间的饮食行为差异很大，更多弱势群体和个人暴露于更多的饮食风险因素。本综述的目的是总结现有的研究，并确定饮食轻推干预的公平效应。方法：在现场环境中进行的轻推干预的系统审查，报告饮食行为的可观察指标，包括对照组，并报告按 PROGRESS-Plus 框架中概述的社会不平等分层的效果大小。检索了两个数据库（scopus、Pubmed）（最后检索时间为 2021 年 6 月），包括 18 篇文章和 19 项研究（k=46 公平性比较）。使用 ROBINS-I 工具评估偏倚风险。鉴于它们在公平性和研究结果方面的异质性，研究在元综合中进行了总结。结果：大多数公平比较（46 个中的 38 个）可用于认知推动。其中大多数（38 次比较中的 22 次）发现，认知推动在或多或少的弱势群体中同样有效；然而，在 38 次比较中的 12 次中，他们偏爱弱势群体。两项关于行为助推的全面比较有利于弱势群体。结论：本综述中发现的饮食轻推干预的不同影响可能导致健康不平等的增加。同时，大量干预措施没有发现公平效应，表明进一步的调节变量可能有助于促进或缓冲公平效应。重要的是，尽管有这些有趣的发现，但本综述清楚地表明，迫切需要更多关于推动干预和健康公平的研究。未来的干预措施应报告按任何社会不平等指标分层的效果大小。