A steep rise in the number of deaths last winter has been widely reported, with The Independent blaming the excess deaths on the "bitter conditions" and The Daily Telegraph reporting that "thousands of over-75-year-olds perished during the coldest winter for nearly 50 years".
The reports are based on figures compiled by the Office for National Statistics (ONS), which show there were an estimated 31,000 excess winter deaths in England and Wales in 2012-13. This is an increase of nearly one-third on the previous winter. Most deaths occurred in people aged 75 and over.
The ONS report links the excess deaths to the bitterly cold weather between January and March 2013, pointing out that March 2013 was the coldest since 1962 with an average monthly temperature of just 2.6°C.
The report was produced by the Office for National Statistics (ONS), an independent body that collects data on the economy, population and society at a national and local level.
One of the organisation's responsibilities is to provide a yearly estimate of the additional number of people who die during the winter months, defined as December to March. The ONS report states that, in common with other countries, more people die in England and Wales in the winter than in the summer.
These deaths are known as excess winter mortality (EWM) figures and are estimated by comparing deaths during this time period with preceding time periods (April to July and August to November).
EWM figures are widely used to inform policy, planning and research in the public sector, in particular to measure the effectiveness of cold weather planning. In addition, charities use excess winter mortality statistics to support a variety of campaigns.
The current bulletin presents provisional figures of excess winter deaths in England and Wales for the winter period 2012-13 and final figures for the winter period 2011-12.
The ONS uses official data on all deaths recorded annually in England and Wales. It compares the number of deaths that occurred in the period from December to March with the average number of deaths that occurred in the preceding August to November and the following April to July.
The report says that:
It reveals that the number of deaths peaked in the first week of January, and that the number of daily deaths was higher than average for a prolonged period between February and April 2013.
The report also looks at trends in EWM over the last 60 years. It shows a decreasing trend in excess winter deaths continuing until 2005-06, after which there has been a gradual rise.
As yet, no figures are available on the causes of excess deaths last winter, which was characterised by a milder than average December followed by a prolonged period of lower than average temperatures.
However, it is widely acknowledged that the majority of excess winter deaths are caused by:
The report points out that the cold has various physiological effects on the body that may lead to death in vulnerable people. For example, previous research associated a colder home temperature with increased blood pressure. Another study found that cold causes the blood to become thicker, which could lead to blood clots (thrombosis). The cold also lowers immune resistance to respiratory infections.
The ONS report states that influenza levels increase in winter. For vulnerable groups, such as the elderly and those with pre-existing health problems, flu can lead to life-threatening complications such as bronchitis and pneumonia.
The strains of influenza viruses were more severe in 2012-13 compared with 2011-12, leading to a greater number of hospitalisations and intensive care admissions than the previous winter.
There were also increases in winter deaths from dementia overall, and specifically Alzheimer's, as well as deaths from accidental falls and injuries linked to wintry conditions. Falls are a common but often overlooked cause of injury in older people.
Although excess winter deaths are related to low temperatures, hypothermia – a dangerous condition in which the body's core temperature falls to dangerously low levels – is not the main cause of excess winter mortality.
The report states that countries with regularly low winter temperatures, such as Finland and Germany, have very low rates of EWM. Conversely, countries with very mild winter temperatures, such as Portugal and Spain, have very high rates of EWM. England and Wales both have higher than average EWM and high variations in seasonal mortality.
There are many reasons why countries with milder winter climates have such a high level of winter mortality. For example, people who live in countries with generally warmer winters tend to take fewer precautions against the cold, such as wearing warm protective clothing.
Countries with milder winters also tend to have homes with poorer thermal efficiency – for example, fewer homes have cavity wall insulation and double glazing – which makes it harder to keep homes warm during the winter. It has been shown that a low indoor temperature is associated with higher EWM from cardiovascular disease in England.
The media reporting of the statistics provided by the ONS was accurate. Commentators across the political spectrum have suggested that there is a link between fuel poverty (the inability to keep a home warm at an adequate level because of a low income) and excess deaths. This potential association was not examined in the ONS report.
If you are 65 or over, it is important to spend most of your time in a warm environment during the winter months. There are a number of things you can do to cope in cold weather.
Keep your main living room at around 18-21°C (65-70°F) and the rest of the house at least 16°C (61°F). If you can't heat all the rooms you use, heat the living room during the day and the bedroom just before you go to sleep.
Regular hot drinks and eating at least one hot meal a day will help keep energy levels up during winter and keep your body warm.
Finally, make sure you get the seasonal flu jab. While not 100% guaranteed, it should reduce your vulnerability to infection.
For more advice and information, visit the NHS Choices Winter Health bundle.