Obesity remains one of the most challenging public health issues of our modern time. Despite the face validity of claims for influence, studies on the causes of obesity have reported the influence of the food environment to be inconsistent. This inconsistency has been attributed to the variability of measures used by researchers to represent the food environments—Researcher-Defined Food Environments (RDFE) like circular, street-network buffers, and others. This study (i.) determined an individual’s Activity Space (AS) (ii.) explored the accuracy of the RDFE in representing the AS, (iii.) investigated the accuracy of the RDFE in representing actual exposure, and (iv.) explored whether exposure to food outlet reflects the use of food outlets. Data were collected between June and December 2018. A total of 65 participants collected Global Positioning System (GPS) data, kept receipt of all their food purchases, completed a questionnaire about their personal information and had their weight and height measured. A buffer was created around the GPS points and merged to form an AS (GPS-based AS). Statistical and geospatial analyses found that the AS size of participants working away from home was positively related to the Euclidean distance from home to workplace; the orientation (shape) of AS was also influenced by the direction of workplace from home and individual characteristics were not predictive of the size of AS. Consistent with some previous studies, all types and sizes of RDFE variably misrepresented individual exposure in the food environments. Importantly, the accuracy of the RDFE was significantly improved by including both the home and workplace domains. The study also found no correlation between exposure and use of food outlets. Home and workplace are key activity nodes in modelling AS or food environments and the relationship between exposure and use is more complex than is currently suggested in both empirical and policy literature.

中文翻译：

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探索影响个人基于 GPS 的活动空间的因素以及研究人员定义的食物环境如何代表活动空间、食品店的暴露和使用

肥胖仍然是我们现代最具挑战性的公共卫生问题之一。尽管声称的影响具有表面有效性，但对肥胖原因的研究报告称，食物环境的影响并不一致。这种不一致归因于研究人员用来表示食物环境的措施的可变性——研究人员定义的食物环境 (RDFE)，如圆形、街道网络缓冲区等。本研究 (i.) 确定了个人的活动空间 (AS) (ii.) 探索了 RDFE 在表示 AS 方面的准确性，(iii.) 调查了 RDFE 在表示实际暴露方面的准确性，以及 (iv.) 探索了接触食品店是否反映食品店的使用情况。数据是在 2018 年 6 月至 12 月期间收集的。共有 65 名参与者收集了全球定位系统 (GPS) 数据，保留了他们购买的所有食物的收据，完成了有关他们个人信息的问卷调查，并测量了他们的体重和身高。在 GPS 点周围创建缓冲区并合并以形成 AS（基于 GPS 的 AS）。统计和地理空间分析发现，离家工作的参与者的 AS 大小与从家到工作场所的欧几里德距离呈正相关；AS 的方向（形状）也受到工作场所从家的方向的影响，个人特征不能预测 AS 的大小。与之前的一些研究一致，所有类型和大小的 RDFE 都不同程度地歪曲了食物环境中的个体暴露情况。重要的，通过同时包含家庭和工作场所域，RDFE 的准确性得到了显着提高。该研究还发现，接触和使用食品店之间没有相关性。家庭和工作场所是建模 AS 或食物环境的关键活动节点，暴露和使用之间的关系比目前在实证和政策文献中提出的更为复杂。