Overview
- The study, published Aug. 26, 2026, analyzed nearly 1 million emergency department and urgent care visits in Chicago from May–September 2011–2023 and identified 33 diagnoses statistically associated with days at or above 92.6°F (33.7°C).
- Some conditions rose sharply on extreme heat days, with several doubling or tripling and accidental gunshot wounds increasing by more than 30-fold, according to the researchers and news summaries.
- Authors used a novel 'heat-wide association' method, modeled on genome-wide scans, to search 1,803 recorded diagnoses without preselecting targets, a technique the team says can be applied to other cities and health datasets.
- The patient sample skewed toward Black residents and women and concentrated visits on Chicago’s West Side, underscoring equity concerns; authors and experts note the results show statistical associations rather than proven causation and may be affected by how diagnoses are coded.
- Researchers and the Defusing Disasters Working Group say the findings imply larger, undercounted heat-related health burdens that could strain health systems and support local actions such as more shade and trees, cooling requirements for housing, and heat protections for outdoor workers.