EARLY-LIFE NEIGHBORHOOD RESOURCES AND LATER-LIFE HEALTH

Abstract

The neighborhoods in which individuals live shape their physical, cognitive, and mental health. However, much of the research on this topic narrowly focuses on participants’ current neighborhoods without considering how the neighborhoods in which they lived earlier in life may also influence their long-term health. Using an assets-based life-course approach, this dissertation evaluates the hypotheses that early-life exposure to two key neighborhood resources, walkability and park access, is associated with better later-life health. Leveraging the unique study design of the St. Louis Baby Tooth Later-Life Health cohort, this work links early-life (ages 5-13) exposure to walkability and park access to later-life (ages 55-77) physical, cognitive, and mental health. One particularly novel aspect of this work is its assessment of historical exposures, which to date has been limited by a lack of reliable objective data dating back far enough to capture the childhood period of current older adults. In short, we extracted relevant features (e.g., the density of street intersections, parks, and other points of interest) from a georeferenced 1969 street map of the St. Louis metropolitan area and then linked them to prospectively collected childhood residential addresses. Walkability was measured as a composite of population density, street intersection density, and point of interest density. Park access was similarly measured as a composite of park density, park proportion, and park proximity. For each exposure, we evaluated associations between the composite measures, as well as each of the component measures, with later-life health outcomes. In Chapter 2, we evaluated the association between early-life walkability and park access with long-term risk of adulthood mortality using data from over 50,000 tooth donors from the original SLBT study. This work showed that living in neighborhoods with higher park density was associated with a reduced risk of both non-accidental and cardiovascular (CVD) mortality after controlling for demographic and neighborhood socioeconomic factors. In Chapters 3 and 4, we examined the associations between early-life neighborhood resources and later-life cognitive function, assessed using the TestMyBrain cognitive battery, and later-life mental health, assessed using the Generalized Anxiety Disorder Screener-7 (GAD-7) and the Patient Health Questionnaire-9 (PHQ-9), respectively. In each study, we found that living in areas with higher park density was associated with better health, underscoring the idea that access to parks and other greenspace in childhood may be a critical asset for long-term health and well-being. Results were less consistent for walkability, with little evidence for benefits on either cognitive function or mental health outcomes when measuring walkability as a composite measure. When using the component measures of walkability, we found that higher intersection density was associated with better cognitive function, higher point of interest density was associated with better mental health, and higher population density was associated with worse cognitive function in everyone and worse mental health in males. Together, these results suggest that while walkability is most often measured as a single composite of many features of the built environment that facilitate walking, it may in fact capture several different aspects that are differentially related to health. We also found that for both walkability and park access, associations with later-life cognitive function were modified by individual-level and neighborhood-level socioeconomic status, with more benefits found for more advantaged groups. While both park access and walkability may be important health assets, understanding their role within the broader socioeconomic context of the neighborhood and region in which they occur is likely crucial for advancing population health. Overall, findings from this collection underscore the importance of early-life neighborhoods for long-term health.