Objectively measured neighborhood greenness in midlife and late life cognitive and brain imaging outcomes for Alzheimer's disease: The Multi-Ethnic Study of Atherosclerosis

阿尔茨海默病（AD）影响超过500万65岁及以上的美国人。邻域 促进健康的生活方式和整个生命过程中的暴露环境可能有助于增加 认知储备，从而预防AD或延迟其发作。邻里“绿化”（密度健康 植被）是一种这样的邻近特征，其可以增加身体活动，改善心理健康， 减少空气污染暴露，增加社会参与，这些因素以前与晚年有关 大脑健康与晚年相比，中年可能是邻里环境的关键时期， 在AD病理学开始之前的期间，更实质性的效果。虽然有限，现存的文献 发现晚年居住在更环保的社区与较低的痴呆风险， 认知功能障碍和认知能力下降，脑萎缩较少，但以前的研究没有 调查了中年时期邻里绿化与晚年大脑健康的关系。因此，本研究旨在 确定1）在中年期间客观测量的社区绿化度是否是积极的（即， 在≥55奥尔兹中，a）整体认知、处理速度、偶发事件 记忆和执行功能（在基线和纵向）;和B）心室容积，总脑容积 从AD感兴趣区域，和白色物质高信号; 2）邻近绿色更强烈 与女性、非白人/西班牙裔以及低收入人群的认知和MRI结果相关。 社会经济地位（SES）;和3）邻里绿化更强烈地与认知 在种族/民族多样性更高、社会经济地位更低的社区， 森林和公园空间。4，200名参与者的地理编码地址数据（追溯收集至1980年） 从纵向，基于人群的多种族研究动脉粥样硬化（梅萨）将被用来创建 从45岁到54岁的平均邻里绿化指标。绿色度将基于 差异植被指数（NDVI），这是一种从ArcGIS中的卫星图像计算的连续测量值。大脑 健康将用认知（整体认知、处理速度、情景记忆、执行能力）来评估。 功能）和脑成像测量（心室容积、AD感兴趣区域的总脑容积、白色 高强度物质）。调整后的随机截距线性回归将检验平均值 邻里NDVI在中年和晚年的认知和脑成像结果，控制 人口统计（例如，年龄、种族/民族和社会经济地位）、地点、社区社会经济地位和人口密度。成像 结果将除以回归前的颅内体积，以说明脑大小的差异。 个体和邻域特征（目标2和3）的效应修改将使用 调整模型中的交互作用项。这项研究的最终目的是提供证据， 可以促进环境，以防止认知能力下降，延迟AD发作，并允许原位老化。

Alzheimer ’s disease (AD) affects over 5 million Americans aged 65 years and older. Neighborhood environments that promote healthy lifestyles and exposures throughout the life course may help increase cognitive reserve and thereby prevent AD or delay its onset. Neighborhood “greenness” (density of healthy vegetation) is one such neighborhood characteristic that may increase physical activity, improve mental health, reduce air pollution exposure, and increase social engagement, factors previously associated with late life brain health. Compared to late life, the midlife may be a critical time for neighborhood environments to have a more substantial effect, during the period prior to the start of AD pathology. While limited, the extant literature has found that residing in greener neighborhoods in late life is associated with lower dementia risk, lower odds of cognitive impairment and cognitive decline, and less brain atrophy, but previous studies have not investigated neighborhood greenness from midlife in relation to late life brain health. Thus, this study aims to determine whether 1) objectively measured neighborhood greenness during midlife is positively (i.e., beneficially) associated among ≥55 year olds with measures of a) global cognition, processing speed, episodic memory and executive function (at baseline and longitudinally); and b) ventricular volume, total brain volume from AD regions of interest, and white matter hyperintensities; 2) neighborhood greenness is more strongly associated with the cognitive and MRI outcomes among women, non-Whites/Hispanics, and those of lower socioeconomic status (SES); and 3) neighborhood greenness is more strongly associated with the cognitive and MRI outcomes in neighborhoods with more racial/ethnic diversity, lower socioeconomic status, and more forest and park space. Geocoded address data (retrospectively collected back to 1980) for 4,200 participants from the longitudinal, population-based Multi-Ethnic Study of Atherosclerosis (MESA) will be used to create measures of average neighborhood greenness from ages 45 to 54. Greenness will be based on the normalized difference vegetation index (NDVI), a continuous measure calculated from satellite imagery in ArcGIS. Brain health will be assessed with cognitive (global cognition, processing speed, episodic memory, executive function) and brain imaging measures (ventricular volume, total brain volume in AD regions of interest, white matter hyperintensities). Adjusted random intercept linear regression will test associations between average neighborhood NDVI in midlife and the late life cognitive and brain imaging outcomes, controlling for demographics (e.g., age, race/ethnicity and SES), site, neighborhood SES, and population density. Imaging outcomes will be divided by intracranial volume prior to regression to account for differences in brain size. Effect modification by the individual and neighborhood characteristics (Aims 2 and 3) will be tested using interaction terms in adjusted models. The ultimate goal of this research is to provide evidence of neighborhood environments that can be promoted to prevent cognitive decline, delay AD onset, and allow aging in place.