Effects of gestational exposure to extreme heat and heat vulnerability on early life blood pressure trajectories

The National Institute of Environmental Health Sciences awarded the University of North Carolina at Chapel Hill $207,384 on September 14, 2025, under the Environmental Health program (CFDA 93.113) to examine how gestational exposure to extreme heat and neighborhood heat vulnerability affect blood pressure trajectories during early childhood.

The research addresses gaps in the literature on the relationship between heat stress exposure and cardiovascular health in children. The study will leverage data from a regional birth cohort with follow-up through early childhood, linked to validated national data on ambient, built, and social environmental exposures. Three aims structure the work: describing trends of extreme heat events and their distribution across sociodemographic characteristics during the study period; investigating associations between gestational extreme heat event exposure and blood pressure outcomes throughout early childhood; and examining how neighborhood heat vulnerability modifies the pathway between heat exposure and blood pressure. The research will advance understanding of environmental mechanisms affecting cardiovascular health and inform future interventions and policy to reduce cardiovascular morbidity from heat exposure.

Work is performed in Chapel Hill, North Carolina. The award period extends through May 13, 2027. This is a Project Grant, a assistance type supporting research by a named principal investigator.

Abstract

With rising temperatures, exposure to ambient extreme heat presents a current and future threat to public health. Research has demonstrated that heat exposure is associated with increased morbidity and mortality, both in causing conditions such as heat exhaustion, heat cramps, and heat stroke and in exacerbating existing conditions including those related to the respiratory, cerebral, and cardiovascular systems. There is little research, however, on the relationship between heat stress exposure and cardiovascular health (CVH), especially among children. Further, research has not investigated how the vulnerability of neighborhood built and social environments to ambient heat may attenuate such a relationship. This study will address the gaps present in the literature by examining how extreme heat exposure is associated with blood pressure, a key indicator of CVH, during early childhood. IT will also explore how neighborhood heat vulnerability acts as both an exposure impacting CVH and a modifier on the pathway between heat exposure and CVH. To do so, this study will leverage data from a regional birth cohort with follow-up through early childhood which will be linked to validated, national data for ambient, built, and social environmental exposures. In aim 1, i will describe trends of extreme heat events throughout the study period and how gestational extreme heat event (EHE) exposure and neighborhood vulnerability are impacted by socioeconomic and racial and ethnic disparities. In aim 2, i will investigate associations between gestational EHE and blood pressure outcomes throughout early childhood. Finally, in aim 3, i will investigate the role of gestational heat vulnerability with EHE and blood pressure. This study will advance our understanding of the mechanisms by which environment can affect CVH. This will inform future interventions and policy to reduce CVH morbidity from a growing public health threat during a sensitive period of life when prevention may be most effective.