Abstract P295: Climate-related Heat Exposure And Cardiovascular Health: A Global Scoping Review
Authors: Graffy Peter M , Sunderraj Ashwin , Visa Maxime A , Miller Corinne , Barrett Benjamin , Rao Sheetal , Camilleri Sara F , Harp Ryan D , Li Chuxuan , Brenneman Anne , Kho Abel , Horton Daniel E , Allen Norrina B 
Published: May 2024

Introduction:
Numerous studies across the world have characterized the effect of extreme heat exposure on cardiovascular health (CVH) using myriad data sources and methodologies. Here we review these studies and synthesize their methodological approaches and findings to identify common clinical factors associated with CVH following extreme heat exposure. Similarities and differences across the different global settings are identified and discussed.

Hypothesis:
CVH is modulated by the exacerbation of clinical cardiovascular health factors due to extreme heat, which will vary according to the study population’s climatological setting.

Methods:
Embase (Elsevier), MEDLINE (Ovid), Web of Science (Clarivate), and Scopus (Elsevier) were searched from date of inception until March 1, 2023 to locate English language literature on heat exposure in relation to cardiovascular vulnerability. Records were collated, deduplicated and screened. Eligibility for full text inclusion was determined as any article with a measured exposure of climate-related heat and an associated clinical outcome, thus excluding review papers and abstracts.

Results:
13,136 records were initially identified of which 341 were determined eligible for full text review. 284 papers were excluded during full text review, yielding 57 papers for the final analysis representing 22 unique country study locations. 34 papers focused on CV-related mortality, 21 focused on CV-related morbidity, and 2 papers assessed both. The most common study type was observational (30), followed by case-crossover (18) and time series (5). A distributed lag non-linear model (DLNM) with a quasi-Poisson regression was the most common analytical methodology with usage in 19 studies. Studies done in Asia more frequently utilized the DLNM methodology while others used generalized additive models and conditional logistic regression. Lag patterns followed a “J” shape with the greatest risk for CVH following extreme heat events occurring at lag days 0-3 and lags 0-21. 97% (33/34) of mortality studies found a significant association with heat, with an excess risk of 6-80% for every 1°C above their respective extreme heat threshold, which was defined as the 99
th
percentile of daily T

mean

in 32% (18/57) of papers. A greater risk of hospitalization and mortality for the elderly was reported across all studies, and women were found to be at greater risk than men for stroke (ischemic and hemorrhagic), circulatory disease, and mortality. The risk of myocardial infarction hospitalizations and MI-related mortality was inconsistent across studies.

Conclusion:
CVH is associated with extreme heat, with variations observed across different global environments. More work on this topic is crucial for informing public health policies and strategies aimed at reducing the burden of heat-induced cardiovascular vulnerability.