Jankowska Marta M, Natarajan Loki, Godbole Suneeta, Meseck Kristin, Sears Dorothy D, Patterson Ruth E, Kerr Jacqueline
Qualcomm Institute, California Institute for Telecommunications and Information Technology, University of California, San Diego, California.
Department of Family Medicine and Public Health, University of California, San Diego, California.
Cancer Epidemiol Biomarkers Prev. 2017 Jul;26(7):1078-1084. doi: 10.1158/1055-9965.EPI-16-0927. Epub 2017 Mar 3.
Environmental factors may influence breast cancer; however, most studies have measured environmental exposure in neighborhoods around home residences (static exposure). We hypothesize that tracking environmental exposures over time and space (dynamic exposure) is key to assessing total exposure. This study compares breast cancer survivors' exposure to walkable and recreation-promoting environments using dynamic Global Positioning System (GPS) and static home-based measures of exposure in relation to insulin resistance. GPS data from 249 breast cancer survivors living in San Diego County were collected for one week along with fasting blood draw. Exposure to recreation spaces and walkability was measured for each woman's home address within an 800 m buffer (static), and using a kernel density weight of GPS tracks (dynamic). Participants' exposure estimates were related to insulin resistance (using the homeostatic model assessment of insulin resistance, HOMA-IR) controlled by age and body mass index (BMI) in linear regression models. The dynamic measurement method resulted in greater variability in built environment exposure values than did the static method. Regression results showed no association between HOMA-IR and home-based, static measures of walkability and recreation area exposure. GPS-based dynamic measures of both walkability and recreation area were significantly associated with lower HOMA-IR ( < 0.05). Dynamic exposure measurements may provide important evidence for community- and individual-level interventions that can address cancer risk inequities arising from environments wherein breast cancer survivors live and engage. This is the first study to compare associations of dynamic versus static built environment exposure measures with insulin outcomes in breast cancer survivors. .
环境因素可能会影响乳腺癌；然而，大多数研究测量的是家庭住所周边社区的环境暴露（静态暴露）。我们假设，随着时间和空间追踪环境暴露（动态暴露）是评估总暴露的关键。本研究使用动态全球定位系统（GPS）以及基于家庭的静态暴露测量方法，比较乳腺癌幸存者在适宜步行和促进休闲的环境中的暴露情况与胰岛素抵抗的关系。收集了圣地亚哥县249名乳腺癌幸存者的GPS数据，为期一周，同时进行空腹采血。在800米缓冲区内，针对每位女性的家庭住址测量其对休闲空间和步行便利性的暴露情况（静态），并使用GPS轨迹的核密度权重进行测量（动态）。在年龄和体重指数（BMI）控制的线性回归模型中，将参与者的暴露估计值与胰岛素抵抗（使用胰岛素抵抗稳态模型评估，HOMA-IR）相关联。与静态测量方法相比，动态测量方法导致建成环境暴露值的变异性更大。回归结果显示，HOMA-IR与基于家庭的、静态的步行便利性和休闲区域暴露测量之间无关联。基于GPS的步行便利性和休闲区域动态测量均与较低的HOMA-IR显著相关（<0.05）。动态暴露测量可能为社区和个体层面的干预措施提供重要证据，这些干预措施可以解决乳腺癌幸存者生活和活动环境中产生的癌症风险不平等问题。这是第一项比较动态与静态建成环境暴露测量与乳腺癌幸存者胰岛素结局之间关联的研究。
