Effect of Urban Form on Exercise and BMI in Black Women

描述（由申请人提供）：人们越来越认识到久坐和肥胖不仅仅是个体问题，而是对环境的反应，使其难以活跃和保持健康的体重。我们将使用来自黑人妇女健康研究（BWHS）的数据，这是一项针对非裔美国妇女的大型前瞻性研究，以解决社区“步行环境”（城市形式，包括街道布局和人行道的存在等因素）影响身体活动水平和体重指数（BMI）的假设，独立于个人水平因素和社区社会经济地位（SES）。该研究将重点关注三个城市（纽约、洛杉矶和芝加哥），因为每个城市都包含一系列社区类型，大约13,000名BWHS参与者居住在那里，并且可以获得有关城市形态的详细数据。一名交通和城市规划专家将为这三个城市编制社区尺度的行人环境数据，包括土地使用的性质和密度、与公园的接近程度、人行道的存在、交通速度和交通量以及街道结构。这些资料将会连结至BWHS参加者的地理编码住址。我们还将把美国人口普查的SES数据与参与者的地址联系起来。我们将使用因子分析来确定一组描述邻里步行环境的变量，这些变量提供互补但不冗余的信息。

DESCRIPTION (provided by applicant): It is increasingly recognized that sedentariness and obesity are not solely individual problems but are responses to an environment that makes it difficult to be active and maintain a healthy weight. We will use data from the Black Women's Health Study (BWHS), a large prospective study of African-American women, to address the hypothesis that the neighborhood "pedestrian environment" (urban form, comprising such factors as street layout and presence of sidewalks) influences levels of physical activity and body mass index (BMI), independent of individual level factors and neighborhood socioeconomic status (SES). The study will focus on three cities (New York, Los Angeles, and Chicago) chosen because each contains a range of neighborhood types, approximately 13,000 BWHS participants live there, and detailed data on urban form are available. An expert in transportation and urban planning will compile data about the pedestrian environment at the neighborhood scale for the 3 cities, including nature and density of land use, proximity to parks, presence of sidewalks, speed and volume of traffic, and street structure. These data will be linked to the geocoded residential addresses of BWHS participants. We will also link U.S. Census data on SES to the participants' addresses. We will use factor analysis to identify a set of variables describing the neighborhood pedestrian environment that contribute complementary but not redundant information. Using multi-level longitudinal regression techniques, we will assess the influence of the pedestrian environment on levels of utilitarian walking, walking for exercise, vigorous activity, sedentariness, moderate activity, BMI, and change in weight, controlling for personal factors and neighborhood SES. We will also assess if an effect of urban form on BMI is mediated through physical activity. The proposed study, the first examination of the influence of urban form on BMI and physical activity in African-American women, is an innovative merging of techniques from the fields of transportation research and epidemiology. BWHS participants in the study cities live in a range of neighborhoods, have a wide range of physical activity levels, and have a wide range of BMI levels, including appreciable numbers of women who are obese. In view of the high prevalence of obesity and physical inactivity in African-American women, elucidation of the role of urban form on physical activity and BMI in this group is of public health importance. Societal level change may be necessary to stem the obesity epidemic, given the failure of interventions at the individual level. To make the case for policy change at the societal level, compelling evidence about the impact of the environment on physical activity and obesity is needed. The proposed study has the potential to provide such evidence and to impact policy in the domains of both transportation/urban planning and public health.