Heat waves in the UK: impacts and public health responses

In August 2003, a severe heat wave resulted in the deaths of more than 14,000 people in France and of many more in neighbouring countries. The UK was fortunate in suffering less oppressive and less unrelenting temperatures, but there were still around 2,000 deaths. Because of global warming, the chance of experiencing a similar heat wave in Britain is increasing, and the lesson from France is that our public health systems may not have been well-prepared to respond to such a threat.
Prompted by the experience of France, the Department of Health launched a heat wave plan for England in 2004. Its provisions include public health warnings and targeted advice and actions to protect those at greatest risk. The study we propose is aimed at providing evidence to help improve how this heat wave plan can be most effective.
Our analyses will quantify the level of heat-related risk for different sections of the population, and so determine the degree to which vulnerability to heat waves is concentrated in high-risk groups that may be targeted by specific protection measures. We will also estimate the risk of dangerous heat waves occurring now and in future years, and assess how we can best detect evolving heat wave threats at an early stage.
A number of (mainly elderly) people and their carers will be interviewed to understand what knowledge they have about the risks and responses to heat waves. We will also assess the operation of the current heat wave plan through semi-structured interviews with key stakeholders, including health and social care professionals, community voluntary workers, and residential home managers. Its cost-effectiveness will be assessed using evidence about the change in the number of heat-deaths occurring during heat waves since the plan was implemented.
The results of the research will be discussed with policy makers and key public health professionals involved in heat wave planning to draw conclusions about how the needed responses of the health, social and other services can be improved.
The results will be made available to the public through non-technical web reports and participation of research team members in policy-focused meetings.

This study is aimed at informing the development of public health responses to heat waves in the UK and in particular the further development of the heat wave plan for England. It will assess the form of heat wave interventions that are most likely to reduce public health impacts in the light of evidence about the distribution of population vulnerability and the cost-effectiveness of interventions.

It will entail the epidemiological analysis of heat-related health impacts and their effect modifiers; the qualitative assessment of heat-related behaviours of vulnerable members of the public; and an evaluation, including through cost-effectiveness analysis, of the current heat wave plan for England.

The principal objectives are: (1) To quantify for England the regional mortality risks associated with periods of high outdoor temperature and, through assessment of the modifiers of such risk, to characterize the degree to which vulnerability to heat episodes is concentrated in high risk groups that may be targeted by specific interventions; (2) To use results from (1) in combination with regional climate models to estimate the frequency of future heat wave events of given mortality impact; (3) To evaluate the use of real time health/health service data in the early detection and response to heat episodes; (4) To compare, using semi-structured interviews, the knowledge and attitudes of high-risk groups and their carers to the health impacts of heat waves and the factors likely to impede or promote protective responses to them; (5) To evaluate the current heat wave plan for England through analysis of quantitative outcome data, document analysis, and semi-structured interviews with key stakeholders in the heat plan cascade, including health and social care professionals, community voluntary workers, and residential home managers; (6) To estimate the impact of the heat wave plan for England in its first four years of implementation through the standardized comparison of the heat-related mortality in 2004-07 with that in pre-implementation years; (7) To estimate the cost-effectiveness of specific heat wave interventions using sensitivity analyses that vary assumptions about targeting and intervention efficacy.

The results will be discussed with policy makers and key public health professionals to draw conclusions from the research about the design of the heat wave action plan, including thresholds for alerts, methods of targeting high risk groups, preparedness/capacity planning, methods of communication, and the need for variation of the plans by social group.