Sadler Richard C, Gilliland Jason A
Department of Family Medicine, Michigan State University, 200 E 1st St, Flint, MI 48502, United States.
Department of Geography, Faculty of Health Sciences, and Department of Paediatrics, University of Western Ontario, 1151 Richmond St, London, ON N6A 5C2, Canada.
Spat Spatiotemporal Epidemiol. 2015 Jul-Oct;14-15:55-61. doi: 10.1016/j.sste.2015.09.001. Epub 2015 Oct 1.
Various geospatial techniques have been employed to estimate children's exposure to environmental cardiometabolic risk factors, including junk food. But many studies uncritically rely on exposure proxies which differ greatly from actual exposure. Misrepresentation of exposure by researchers could lead to poor decisions and ineffective policymaking. This study conducts a GIS-based analysis of GPS tracks--'activity spaces'--and 21 proxies for activity spaces (e.g. buffers, container approaches) for a sample of 526 children (ages 9-14) in London, Ontario, Canada. These measures are combined with a validated food environment database (including fast food and convenience stores) to create a series of junk food exposure estimates and quantify the errors resulting from use of different proxy methods. Results indicate that exposure proxies consistently underestimate exposure to junk foods by as much as 68%. This underestimation is important to policy development because children are exposed to more junk food than estimated using typical methods.
各种地理空间技术已被用于估计儿童接触环境心脏代谢风险因素的情况，包括垃圾食品。但许多研究不加批判地依赖与实际接触情况有很大差异的接触代理。研究人员对接触情况的错误表述可能导致决策失误和政策制定无效。本研究对加拿大安大略省伦敦市526名9至14岁儿童的样本进行了基于地理信息系统（GIS）的全球定位系统（GPS）轨迹——“活动空间”——以及21种活动空间代理（如缓冲区、容器法）的分析。这些测量结果与经过验证的食品环境数据库（包括快餐店和便利店）相结合，以创建一系列垃圾食品接触估计值，并量化使用不同代理方法所产生的误差。结果表明，接触代理始终将垃圾食品的接触量低估多达68%。这种低估对政策制定很重要，因为儿童接触的垃圾食品比使用传统方法估计的要多。
