What is the Evidence on Applicability and Effectiveness of Public Health Interventions in Reducing Morbidity and Mortality during Heat Episodes?

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Heat events are associated with a diverse range of adverse health effects including excess mortality as well as many symptoms falling under the broad umbrella of “heat-related illness”. Although these effects are most marked in vulnerable populations like the elderly, socially
isolated, and homeless, everyone is at risk to varying degrees. This negative impact of heat on health continues to be a persistent concern and is expected to become even more pressing in the future given the predicted meteorological changes linked to climate change.

This work is to summarize the current state of knowledge and to provide practitioners with information that is relevant for policy and practice, with a focus on evidence of the applicability and effectiveness of related public health interventions.

Minimal work has been done on the effectiveness of interventions, largely due to difficulties in evaluation. There is no standard definition for a heat episode or for heat-related illness. Heat episodes are rare events with varying impacts on different populations and geographical regions. As no two heat episodes are the same, challenges arise in attributing changes in health outcomes to interventions versus differences in weather conditions or in study design. Typically several interventions are implemented rather than only one, making it difficult to evaluate. There is an important role for longer-term strategies like environmental modifications.

In the evaluation findings, most members of the public were aware when an extreme heat episode was occurring, as a result of broadcast media messages. However, less than half of these people actually reported changing behaviour in response. This was attributed to a perception that they are not part of a vulnerable group and to confusion around the meaning of the messages and actions. This included groups at greatest risk; such as, the elderly. It is not known whether these messages even reach the most vulnerable (e.g., socially isolated populations and the homeless).

Heat health warning systems (HHWS) and their associated public health interventions were all associated with reduced mortality. Less certain were the causal relations between specific activities and mortality reduction, as well as which interventions protect which vulnerable groups. Intervention effects on morbidity were positive but limited to one study only. Some activities work well in certain communities while others are not as effective. For example, many elderly in large cities do not feel safe leaving their homes at night to visit an emergency cooling centre, but other age groups or individuals in other neighbourhoods do not necessarily share this concern. For this reason, locales need to develop interventions that are tailored to their community.

Recommendations: 1) developing a national clearinghouse with guidelines defining a heat episode, guidelines for setting up a local HHWS, and suggestions for potential health interventions; 2) coordinating evaluations of heat response plans nationally; and so developing a framework with draft criteria which could be applied to a selection of public health sites that have heat interventions in place to assess their utility as an evaluation framework.

Journal Article

Publication Date Apr 19, 2007
Author Bassil K, Cole DC, Smoyer-Tomic K, Callaghan M, Heat Episode Public Health Intervention Team
Posted by NCCEH Sep 02, 2008