UCL Institute for Environmental Design and Engineering


Excess winter deaths (EWD)

30 November 2016

Key facts

  • Funding Body/Client: National Institute for Clinical Excellence (NICE) 
  • Project Partners: London School of Hygiene and Tropical Medicine (LSHTM), Public Health England (PHE) 
  • Total Project Value: £100,000
  • UCL/IEDE Project Value Share: £30,000
  • Duration: 2013-2014 
  • Status: Complete

In the UK, the definition of excess winter death (EWD) is often based on an index comparing the rate of death in the winter months (conventionally taken as December to March for EWD) to that in other months of the year. However, this simple index reflects only part of a complex picture of variation in health events occurring across the year driven by a range of factors which may include (among others) the weather, seasonal infections, air pollution, behavioural changes and micronutrient levels. Of these, the most important and best understood contributor to EWD and morbidity in years without an influenza epidemic is the effect of low temperature.  

Despite indirect evidence that housing is important, its role in excess winter death has yet to be conclusively established, though there is evidence of adverse psycho-social impacts of cold homes.

The aim of this work is to carry out an evidence review and economic analysis of EWD to enable NICE to produce guidelines that will provide recommendations for good practice. The guidelines will be aimed at commissioners, managers and practitioners with public health as part of their remit working within the NHS, local authorities and the wider public, private, voluntary and community sectors. It may also be of interest to members of the public.


PI: Paul Wilkinson (LSHTM)

Co-I: Michael Davies (UCL)

RRs: Ben Armstrong (LSHTM), John Cairns (LSHTM), Zaid Chalabi (LSHTM), Shakoor Hajat (LSHTM), Lorelei Jones (LSHTM), James Milner (LSHTM), Mark Petticrew (LSHTM), Sotiris Vardoulakis (LSHTM), Bernd Egger (LSHTM), Virginia Murray (LSHTM), Ian Hamilton (UCL) and Payel Das (UCL) 


The evidence reviews identified a number of factors that appear to contribute to vulnerability to seasonal- and cold-related mortality/morbidity, which can help in the development of health protection strategies. The relative flatness of the relationship with socio-economic factors, the importance of age, and the wide range of health outcomes affected, suggest that the risk of winter- and cold-related mortality/morbidity is fairly widely distributed, especially in the elderly population. Evidence on interventions to reduce winter-and cold-related mortality/morbidity remains limited and the overall economic assessment of those interventions is likely to depend in large measure on how health and non-health costs and benefits are counted. Modelling suggests however that a wide range of measures and approaches could be important for tackling winter-and cold-related mortality and morbidity, with contributions across multiple agencies and sectors.  

Among others, those include the health and care services, local authorities, the community and voluntary sector, those involved in emergency planning and preparedness, as well as carers and neighbours of vulnerable people.  There appears to be a role to support high risk individuals during periods of greater risk (e.g. very cold or icy/snowy weather), as well as the improvement of understanding of risks and protection measures against cold-related risks in the population as a whole.  Long term measures, including infrastructure investments such as the improvement of home energy efficiency, are important as population-wide measures, but may also be targeted to help maximize impact especially for vulnerable groups. 


The evidence reviews and economic modelling have directly informed guidelines on EWD and illnesses, for which the consultation period is between 13th June to 25th July 2014 (https://www.nice.org.uk/Guidance/GID-PHG70/Consultation). 


Read more about NICE guidance

For Further information please contact: Michael Davies