Department of Nutrition, University of North Carolina at Chapel Hill, Carolina Population Center, 123 West Franklin St,, Campus Box 8120, Chapel Hill, 27516-3997, USA.
Int J Behav Nutr Phys Act. 2010 Oct 4;7:70. doi: 10.1186/1479-5868-7-70.
Built environment research is dominated by cross-sectional designs, which are particularly vulnerable to residential self-selection bias resulting from health-related attitudes, neighborhood preferences, or other unmeasured characteristics related to both neighborhood choice and health-related outcomes.
We used cohort data from the National Longitudinal Study of Adolescent Health (United States; Wave I, 1994-95; Wave III, 2001-02; n = 12,701) and a time-varying geographic information system. Longitudinal relationships between moderate to vigorous physical activity (MVPA) bouts and built and socioeconomic environment measures (landcover diversity, pay and public physical activity facilities per 10,000 population, street connectivity, median household income, and crime rate) from adolescence to young adulthood were estimated using random effects models (biased by unmeasured confounders) and fixed effects models (within-person estimator, which adjusts for unmeasured confounders that are stable over time).
Random effects models yielded null associations except for negative crime-MVPA associations [coefficient (95% CI): -0.056 (-0.083, -0.029) in males, -0.061 (-0.090, -0.033) in females]. After controlling for measured and time invariant unmeasured characteristics using within-person estimators, MVPA was higher with greater physical activity pay facilities in males [coefficient (95% CI): 0.024 (0.006, 0.042)], and lower with higher crime rates in males [coefficient (95% CI): -0.107 (-0.140, -0.075)] and females [coefficient (95% CI): -0.046 (-0.083, -0.009)]. Other associations were null or in the counter-intuitive direction.
Comparison of within-person estimates to estimates unadjusted for unmeasured characteristics suggest that residential self-selection can bias associations toward the null, as opposed to its typical characterization as a positive confounder. Differential environment-MVPA associations by residential relocation suggest that studies examining changes following residential relocation may be vulnerable to selection bias. The authors discuss complexities of adjusting for residential self-selection and residential relocation, particularly during the adolescent to young adult transition.
建筑环境研究主要采用横断面设计，这种设计特别容易受到与健康相关的态度、邻里偏好或其他与邻里选择和健康相关结果相关的未测量特征的影响，从而导致居住者的自我选择偏差。
我们使用了来自美国青少年健康纵向研究（National Longitudinal Study of Adolescent Health，NLAHS）的队列数据（第 1 波，1994-1995 年；第 3 波，2001-2002 年；n=12701）和一个时变地理信息系统。使用随机效应模型（受未测量混杂因素影响）和固定效应模型（个体内估计器，可调整随时间变化的未测量混杂因素），估计了青少年到青年期期间，中等到剧烈体力活动（MVPA）与建筑和社会经济环境指标（土地覆盖多样性、每 10000 人支付的公共体育活动设施、街道连通性、家庭中位数收入和犯罪率）之间的纵向关系。
随机效应模型得出的结果均为零关联，只有犯罪与 MVPA 的关联呈负相关[男性为-0.056（-0.083，-0.029），女性为-0.061（-0.090，-0.033）]。使用个体内估计器控制测量和时不变的未测量特征后，男性中与较高的体力活动薪酬设施相关的 MVPA 更高[系数（95%置信区间）：0.024（0.006，0.042）]，而男性的犯罪率较高[系数（95%置信区间）：-0.107（-0.140，-0.075）]和女性[系数（95%置信区间）：-0.046（-0.083，-0.009）]的 MVPA 则更低。其他关联为零或呈反直觉方向。
与未调整未测量特征的个体内估计值相比，比较表明，居住者的自我选择可能会使关联偏向于零，而不是通常将其描述为正向混杂因素。根据居住地点的变化，环境与 MVPA 的关联存在差异，这表明研究在居民搬迁后发生变化的研究可能容易受到选择偏差的影响。作者讨论了调整居住者自我选择和居民搬迁的复杂性，特别是在青少年到青年期过渡期间。
