Nationwide Associations between Multiple Co-Occurring Climate Threats and Neurodegeneration

Project 1 – Summary Climate change is and will remain the most important threat to human health. As emissions keep driving tem- peratures higher, climate threats (e.g., wildfires, heat waves, hurricanes, flooding, etc) are increasing in inten- sity and most of these in frequency as well. Several climate-relevant exposures have been linked to adverse

health outcomes, such as mortality, cardiovascular disease, and mental health. Although some preliminary evi- dence and biological plausibility exist, the association between climate-relevant exposures and neurodegener- ation has not been fully investigated. Furthermore, most existing studies characterizing the impacts of climate

threats on adverse health outcomes have focused on a single exposure at a time. However, many of these cli- mate events co-occur (compound events), with variation across space and time. Health analyses that charac- terize the overall impact of exposure to multiple climate threats simultaneously, thus, are critical to fully under-

standing the impact of climate threats on neurodegeneration. Importantly, performing analyses with a climate justice lens is critical for equitable solutions for protection and mitigation. We will address these critical re- search, methodological, and knowledge gaps as part of Project 1. To do so, we will leverage nationwide data

on multiple climate-relevant exposures (temperature, temperature variability, heat and cold waves, wildfires, tropical cyclones, Nor’easters, flooding, droughts, tornadoes, extreme precipitation, and secondarily air pollu- tion) and Medicare claims since 2000. We will focus on Alzheimer’s disease and related dementias (ADRD) as

the main neurodegenerative outcome of interest. Complementary to this approach, we will also leverage well- characterized cognitive function outcome data in the Washington Heights/Inwood Columbia Aging Project (WHICAP), a prospective study of aging and dementia. Specifically, we will (1) characterize spatio-temporal

patterns in co-occurrence of climate threats across the US (2000–2020) and develop climate region-specific indices of exposure to multiple co-occurring climate threats (climate threat index, CTI); (2) investigate the as- sociation between short-term exposure to multiple co-occurring climate threats and ADRD-related hospitaliza-

tions; and (3) examine the association between multiple climate exposures and cognitive function among WHICAP participants. Housing is a major pathway through which health disparities emerge and are sustained. Housing characteristics and conditions are modifiable; identifying those housing characteristics and conditions

that are associated with worse climate change-induced adverse health outcomes can lead to equitably actiona- ble solutions. We will examine, thus, whether the identified patterns of co-occurring climate threats, CTI, and the examined associations with ADRD-related hospitalizations and cognitive function vary by housing charac-

teristics and conditions. We expect that our findings will provide actionable insights and help guide equitable and efficient interventions, investments, and mitigation plans for protecting the people and communities who are most vulnerable to climate threats.