Extreme heat is a significant public health threat that is expected to worsen due to climate change. To reduce heat-related morbidity and mortality, the United States (US) National Weather Service (NWS) typically issues heat warnings to communicate risks to the public when the heat index (HI) for the next day is forecast to be above a threshold value. However, few studies have examined whether heat warnings prevent deaths, and no studies have examined whether heat warnings prevent morbidity. Accordingly, we propose to quantify the public health benefit of heat warnings issued by NWS in the large, national population of Medicare beneficiaries. As heat warnings are issued based on forecast HI, and forecasts are sometimes wrong, in any given location there exists a set of hot days of similar HI with and without heat warnings. We will take advantage of this data structure by using case-crossover analyses to compare days of similar HI with and without heat warnings. Specifically, we will address the following Specific Aims using all deaths and all emergency hospitalizations among Medicare beneficiaries between 2001 and 2012 in 207 US cities.
In Aim 1, we will assess whether heat warnings are associated with reduced risk of death among US Medicare beneficiaries.
In Aim 2, we will assess whether heat warnings are associated with reduced morbidity as assessed by risk of emergency hospitalization among US Medicare beneficiaries.
In Aim 3, we will assess how the benefits of heat warnings vary across levels of individual, community, and meteorologic characteristics. To accomplish these Aims, this proposal will leverage a valuable but previously unutilized data source: a national database of text records of heat warnings issued by the NWS. This proposed research is significant because the findings will provide public health and emergency preparedness officials across the country with critical information they need to better protect the public's health during extreme heat events. For example, the results have the potential to inform NWS policy regarding the criteria for issuing warnings and the frequency with which warnings are issued. The results could further inform actions taken by local health and emergency management offices to mitigate the impact of extreme heat events, such as the development of heat preparedness and response plans. This proposed research is well- aligned with NIEHS's strategic goal of identifying and responding to emerging environmental threats to human health.

Public Health Relevance

This project is relevant to public health because it will increase knowledge about strategies that local weather forecasting offices and policy-makers can take to protect the health of older Americans during episodes of extreme heat. This knowledge will be especially critical as the frequency and intensity of extreme heat increases due to climate change.

National Institute of Health (NIH)
National Institute of Environmental Health Sciences (NIEHS)
Postdoctoral Individual National Research Service Award (F32)
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Special Emphasis Panel (ZRG1)
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Boyles, Abee
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Brown University
Public Health & Prev Medicine
Schools of Public Health
United States
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Spangler, Keith R; Weinberger, Kate R; Wellenius, Gregory A (2018) Suitability of gridded climate datasets for use in environmental epidemiology. J Expo Sci Environ Epidemiol :
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Weinberger, Kate R; Haykin, Leah; Eliot, Melissa N et al. (2017) Projected temperature-related deaths in ten large U.S. metropolitan areas under different climate change scenarios. Environ Int 107:196-204