A National Assessment of Exposure-Response Relationships for Heat-related Health Outcomes

From a public health prevention perspective, issuing heat alerts at temperature ranges that correspond with health risks and planning outreach efforts to communicate adverse health impacts associated extreme heat will strengthen preparedness, response, and recovery capacity among state and local agencies dealing with extreme heat-related emergencies.

We have conducted a region-specific epidemiologic risk assessment that explores the development of exposure-response (E-R) relationships between extreme heat and a wide range of health outcomes. The assessment’s primary objective was to identify extreme heat temperature ranges that are appropriate from a public health perspective for various health outcomes. Toward this objective, a community-specific time-series analysis, was used to develop E-R relationships between extreme heat and range of health outcomes for different locations in the U.S. The risk estimates were pooled to generate state-specific E-R relationships.

Our results suggest that there is a non-linear E-R relationship between heat index and heat-related health outcomes. This assessment indicates that in some locations, there is a discrepancy between existing alert criteria and temperature range at which health risks becomes significant. For example, in the State of Georgia, heat alerts are typically issued when the heat index value reaches 105 °F; however the health risk starts to increase at heat index values well below 90 °F.

The results from this analysis can be used to develop an online Decision Support Tool (DST) for mitigating adverse health impacts associated with extreme heat. In addition, these temperature ranges that are appropriate from a health perspective will be shared with National Weather Service (NWS) to help identify divergences in existing heat warning systems as well as identify potential solutions to mitigate health burden resulting from extreme heat.