JMIR Publications

ABSTRACT

Background:

High ambient temperature is a well-recognized environmental hazard to human health, and urban residents may face an increased risk of exposure. There are a variety of health outcomes associated with heat exposure, and an individual’s susceptibility to heat-related illness (HRI) depends on many factors. While previous research is informative for understanding a population’s health risks in relation to heat, it does not describe all the points along the exposure pathway that may be targeted to prevent adverse health outcomes.

Objective:

The goal of this case-control study is to examine risk factors for heat-related emergency department visits that are not captured through medical records, such as how and why exposure occurred.

Methods:

Cases are patients presenting to emergency departments (ED) for HRI at seven Atlanta-area hospitals. For each case, a matched control is recruited who experienced a non-HRI visit on the same date as the case ED visit, with same age, sex, and ZIP code or county of residence. Medical history is pulled from each participant’s electronic medical record. All participants complete a 65-question survey addressing their baseline health status, experience of past HRI, and other characteristics that may be related to HRI. Risk factors for HRI are identified quantitatively by comparing survey responses of cases and controls. Cases also complete structured interviews to provide additional qualitative context for their HRI experience. Qualitative analyses identify themes in the interview data. Findings from the quantitative and qualitative analyses are integrated to bilaterally support and deepen our understanding of HRI risk factors.

Results:

The study commenced in May 2024 with a recruitment goal of 200 cases and 200 matched controls. As of September 2025, 55 cases with 50 controls have been enrolled. Between May-September 2024 and 2025, 236 HRI ED visits were made, resulting in a 23% enrollment rate for cases. Recruitment will continue through September 2026 and data analysis and publication will follow.

Conclusions:

This study will provide a better understanding of the risk factors that lead to HRI that is severe enough to result in an emergency department visit. Understanding these risk factors can aid in the development of clinical and public health interventions to reduce HRI.