Diabetes mellitus is a major health problem; nearly half of adults in the U.S. have either diabetes or pre- diabetes. The link between adiposity and the development of Type 2 diabetes (T2DM) is well characterized, but less is known about the impact of environmental factors on risk of T2DM. Research increasingly implicates traffic-related air pollutants (TRAP) with increased risk of T2DM?especially in vulnerable urban populations, but studies thus far have wide ranges of results or have substantial methodological limitations. Other community-scale environmental factors, including aspects of the built and natural environment are also potential risk or protective factors for T2DM and may act through interactions with physical activity, diet and visceral adiposity. This study will incorporate state-of-the-art environmental exposure assessment with detailed health measures and data on potential confounders, including genetic susceptibility, to study these relationships---in a comprehensive framework?focusing on a fast-growing population at disproportionate risk of T2DM risk, through the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) cohort. HCHS/SOL provides a longitudinal assessment of glycemic control along with a broad range of clinical, anthropometric, and psychosocial factors, and begin a third comprehensive clinical exam in early 2020. This proposal adds a multi-dimensional environmental assessment to the HCHS/SOL cohort, effectively leveraging the planned examination and other funded ancillary studies. Through air pollution monitoring and modeling, accelerometry data, GPS logging, genetic cluster analysis, and advanced geostatistical approaches, the proposal takes advantage of extraordinary set of available resources to measure physical activity (amount and location), individual TRAP exposure, built environment features, genetic susceptibility, and health measures concurrently. The objective of ?SOLAir? is a series of hypothesis-driven, policy-relevant analyses, to understand the environmental influences on T2DM, applying a theoretical framework that includes the interplay between environmental factors and physical activity. This proposal will address the following aims: 1) to assess whether long-term exposures to traffic-related air pollutants (TRAP) increase risk of pre-diabetes and T2DM among Latinos; 2) to determine how environmental factors interact with physical activity to influence T2DM risk; and 3) to examine whether environmental factors contribute differently to sub-types of T2DM identified by genetic clusters, phenotypic characteristics, and metabolomic features.
Environmental factors that can be modified at community-scale, including air pollution and features of the built and natural environment, may affect the risk of developing diabetes. Better understanding of the relationship between environmental factors and diabetes will help in the development of cost-effective policies to protect public health and reduce health inequality?critical parts of the NIH mission. This study will investigate these relationships in Hispanic Community Health Study/Study of Latinos and help to understand the inter- relationship between development of diabetes and traffic-related air pollution, the neighborhood built environment, and the intensity and location of physical activity.
