Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom.
PLoS Med. 2022 Mar 24;19(3):e1003951. doi: 10.1371/journal.pmed.1003951. eCollection 2022 Mar.
The proportion of energy from free sugars and saturated fat currently exceeds the UK-recommended intake across all age groups. Recognising the limits of reformulation programmes, the government in England has announced their intention to introduce legislation to restrict the promotion of foods high in free sugars, salt, and saturated fats in prominent store locations. Here, we evaluated a grocery store intervention to remove seasonal confectionery from prominent locations within a major UK supermarket.
A nonrandomised controlled intervention study with interrupted time series (ITS) analysis was used. Data were analysed from 34 intervention stores located in 2 London boroughs and 151 matched control stores located elsewhere in the UK owned by the same retailer. Stores were matched based on store size and overall sales during the previous year. Between 15 February 2019 and 3 April 2019 (before Easter), stores removed free-standing promotional display units of seasonal confectionery from prominent areas, although these products were available for purchase elsewhere in the store. Store-level weekly sales (units, weight (g), and value (£)) of seasonal chocolate confectionery products were used in primary analyses, with data from 1 January 2018 to 24 November 2019. Secondary outcomes included total energy, fat, saturated fat, and sugars from all in-store purchases. Multivariable hierarchical models were used to investigate pre/post differences in weekly sales of confectionery in intervention versus control stores. ITS analyses were used to evaluate differences in level and trends after intervention implementation. Over a preintervention baseline period (15 February 2018 to 3 April 2018), there were no significant differences in sales (units, weight, and value) of all chocolate confectionery between intervention versus control stores. After intervention implementation, there was an attenuation in the seasonal increase of confectionery sales (units) in intervention stores compared to control (+5% versus +18%; P < 0.001), with similar effects on weight (g) (+12% versus +31%; P < 0.001) and value (£) (-3% versus +10%; P < 0.001). ITS analyses generally showed statistically significant differences in the level at the point of intervention (P ranges 0.010 to 0.067) but also in the trend afterwards (P ranges 0.024 to 0.053), indicating that the initial difference between intervention and control stores reduced over time. There was a significant difference in level change in total energy sold, adjusted for the total weight of food and drink (kcal/g, P = 0.002), and total fat (fat/g) (P = 0.023), but no significant changes in saturated fat or sugars from total sales in ITS models. There was no evidence that the main results varied across store deprivation index. The limitations of this study include the lack of randomisation, residual confounding from unmeasured variables, absolute differences in trends and sales between intervention versus control stores, and no independent measures of intervention fidelity.
Removal of chocolate confectionery from prominent locations was associated with reduced purchases of these products, of sufficient magnitude to observe a reduction in the energy content of total food purchases. These results from a "real-world" intervention provide promising evidence that the proposed legislation in England to restrict promotions of less healthy items in prominent locations may help reduce overconsumption.
目前，所有年龄段人群从游离糖和饱和脂肪中获取的能量比例均超过了英国的推荐摄入量。鉴于配方调整计划的局限性，英格兰政府已宣布打算出台立法，限制在主要商店位置对高游离糖、盐和饱和脂肪含量的食品进行促销。在这里，我们评估了一项杂货店干预措施，即在英国一家大型超市的主要位置去除季节性糖果。
本研究采用非随机对照干预试验与中断时间序列（ITS）分析。数据来自位于伦敦两个行政区的 34 家干预商店和英国其他地区的 151 家匹配控制商店。这些商店是根据前一年的商店规模和整体销售额进行匹配的。2019 年 2 月 15 日至 3 月 4 日（复活节前），商店从显眼位置移除季节性糖果的独立促销展示单元，但这些产品仍可在店内其他地方购买。主要分析采用季节性巧克力糖果产品的每周商店销售额（单位、重量（g）和价值（£）），数据来自 2018 年 1 月 1 日至 2019 年 11 月 24 日。次要结果包括店内所有购买产品的总能量、脂肪、饱和脂肪和糖。使用多变量分层模型来研究干预与对照商店中糖果每周销售额的预/后差异。ITS 分析用于评估干预实施后的水平和趋势差异。在干预前的基线期（2018 年 2 月 15 日至 2018 年 3 月 4 日），干预与对照商店之间的所有巧克力糖果的销售（单位、重量和价值）均无显著差异。干预实施后，与对照商店相比，干预商店季节性糖果销售（单位）的增长有所减弱（+5%对+18%；P < 0.001），重量（g）（+12%对+31%；P < 0.001）和价值（£）（-3%对+10%；P < 0.001）也有类似的影响。ITS 分析通常显示干预点水平（P 值范围为 0.010 至 0.067）存在统计学上的显著差异，并且随后的趋势也存在差异（P 值范围为 0.024 至 0.053），这表明干预和对照商店之间的初始差异随着时间的推移而缩小。干预前后总能量销售的变化水平有显著差异，经调整后的总食物和饮料重量（千卡/g，P = 0.002）和总脂肪（脂肪/g）（P = 0.023），但在 ITS 模型中，总销售额的饱和脂肪或糖无显著变化。没有证据表明主要结果在商店贫困指数之间存在差异。本研究的局限性包括缺乏随机分组、未测量变量的残余混杂、干预与对照商店之间趋势和销售额的绝对差异，以及对干预真实性的独立测量。
从显眼位置去除巧克力糖果与这些产品购买量的减少有关，其减少幅度足以观察到总食品购买量中能量含量的降低。这项“真实世界”干预研究提供了有希望的证据，表明英格兰拟议的立法限制在主要位置对不健康食品的促销活动，可能有助于减少过度消费。
