Children’s Cardiovascular Health in a Changing Climate: The Impacts of Extreme Heat and Wildfire Smoke - PROJECT ABSTRACT Climate change is rapidly intensifying, and climate-related hazards and environmental exposures are expected to significantly impact multiple facets of child health and development. Over the last decade, the US has experienced the highest temperatures on record and more extreme heat events, while at the same time, wildfires have increased in severity, frequency, intensity, and extent, due to our changing climate. As these trends are projected to increase, the impacts of climate-related exposures on children’s health remain largely unknown. Exposure to heat stress and wildfire smoke are emerging climate-related threats that have been strongly linked to adverse cardiovascular health outcomes and mortality in adults. Given that childhood is a critical period in determining life-long cardiovascular health, and children are uniquely sensitive to environmental insults, it is crucial to develop a greater understanding of the cardiovascular impacts of climate-related extreme heat and wildfire smoke, particularly during sensitive periods of development. Further, climate-related exposures often co- occur and evidence suggests that the combined impacts of heat stress and wildfires may heighten the effects of each of these exposures on cardiovascular health, thus considering their cumulative effects is important to fully capture the extent of their likely impacts as climate change accelerates. Lastly, evaluating the efficacy of household and community adaptation strategies at buffering those health effects in children may provide further insight into intervention opportunities to protect the most vulnerable. In this proposal, we will investigate whether greater individual and combined exposures to heat stress and wildfire smoke over the life course and during sensitive developmental windows in pregnancy and childhood are associated with poorer cardiovascular health profiles in mid-childhood. We will leverage the MADRES prospective cohort of predominantly Hispanic, lower- income mother-child pairs to annually evaluate children between ages 6 to 9 years, using a comprehensive set of cardiovascular health measures, including blood pressure, pulse wave velocity, resting heart rate, blood lipids and urinary biomarkers of oxidative stress. We will employ novel statistical modeling methods to evaluate combined exposures during sensitive developmental windows, as well as the role of multi-faceted adaptation strategies, and conversely vulnerabilities, at the household (air conditioning, filtration) and community levels (climate and social vulnerability indices, urban heat islands, tree cover, cooling centers, etc.) in modifying the impacts of climate-related exposures on child cardiovascular health. This work will inform targeted interventions to reduce cardiovascular health impacts of heat stress and wildfire exposures, increase adaptive capacity, and protect long term cardiovascular health among children as climate change intensifies.