ProNurse

By Jeremy Laurance

If you feel weak in the winter and sick in the summer, you are not imagining it. The weather really does affect our health – and can be lethal. By Jeremy Laurance

For a weather-conscious nation we are comically bad at coping with snow and ice. Traffic jams, grit shortages and school closures are part of the British winter landscape.

But it is not only our routine that suffers. So does our health. Cold temperatures lower immunity and thicken the blood, increasing the risk of infection and heart attacks. Grey skies depress mood, icy conditions increase injuries.

Weather can affect health in any season – and in ways that are unexpected. The storm that blows in from the Atlantic, the anticyclone that builds above the North Sea or the pall of cloud that lingers for days may all have an impact. An icy snap in winter or a heatwave in summer can cost hundreds of lives.

The Met Office established a department of health forecasting eight years ago to help identify the threats posed by changes in the weather and protect the vulnerable. The service is being expanded each year and now provides early warning of adverse conditions to tens of thousands of vulnerable people, by phone, email and text message.

Winter Cold

The threat is greatest to those most vulnerable to the cold – people with chronic health conditions such as heart disease. There are more heart attacks in cold weather – blood vessels in the skin contract in the cold to preserve heat, making it harder for the heart to pump the blood round the body. But it is not the cold alone that is the killer – it is the cold combined with high levels of circulating viruses that poses the greatest threat. Cold depresses the immune system and makes us more vulnerable to infection. The Met Office sends alerts to 30,000 people at risk when snow and ice are on their way and virus levels, as measured by the Health Protection Agency, are high. Paid for by Primary Care Trusts, the individuals receive an automated telephone call asking if they are well and whether they have enough medication to last at least two weeks. Their answers are relayed to their GPs, who can respond as necessary.

Wayne Elliott, the head of health forecasting at the Met Office, says: “It is a bespoke service for people suffering from chronic bronchitis and other respiratory conditions. We have rolled it out from the Moray Firth in Scotland to the Scilly Isles in the south. We use a formula that calculates the risk. It is normal most of the year but when the cold weather and high virus levels combine and it becomes ‘elevated’, that triggers the calls. It is much more sophisticated than the general cold weather warnings we issue through the media and our website.”

Around 25,000 extra people die in the winter months compared to other times of the year in England and Wales. Last year there were 40,000 excess deaths, as a result of the unusually low temperatures. Extra deaths also occur during heatwaves in summer, but they are different – the result of what is called “death displacement”. Evidence shows that summer heatwave deaths tend to involve people who would have died soon anyway – and are followed by a dip in deaths during the months after a heatwave.

Winter deaths, by contrast, are genuinely “excess” – they are not followed by a dip in the subsequent months. And they are worse in Britain than in countries with colder winters, such as Scandinavia.

Gloomy skies

Dull days are depressing for anyone, and make it hard to remember the warmth and brightness of last summer’s sunshine. But for some, gloomy weather can make them mentally ill.

A second service offered by the Met Office provides alerts when two or more gloomy days are forecast for individuals who suffer depression or other mental problems in winter – Seasonal Affective Disorder (SAD) is the technical term. Those signed up to the scheme are provided with a light box, a manual for cognitive behaviour therapy [self-administered] and an information leaflet on the importance of eating well and exercise, paid for by their primary care trusts.

Mr Elliott admits he was a late convert to the cause, but is now convinced of the value of the service and is looking for new primary care trusts to adopt it, especially in Scotland – arguably the gloomiest place in the British Isles. “Two years ago we were approached by Cornwall PCT who had reviewed their mental health services and found this issue – the weather – came very high up in the list of factors that people said affected their mood. It was across the spectrum from those with severe psychosis to people complaining of poor performance and irritability at work. We ran a pilot scheme in Cornwall with 90 people last year and this year we are extending it to over 200 in Trafford, Bracknell and Manchester as well as Cornwall again. When an extended period of gloomy weather is forecast lasting two or more days we alert them by text message or email – they tend to be younger than the respiratory disease patients – to get their light boxes out.”

The light boxes emit a much stronger light than ordinary electric bulbs, which is thought necessary to banish the winter blues. However, the evidence is equivocal and many doctors think any benefit is due to the placebo effect.

Mr Elliott is unabashed. “A lot of it is psychological – but I am an absolute defender of that being important. If patients are reporting that they feel better with the treatment then it is worth doing.”

He adds: “We don’t see much innovation in mental health compared with areas such as cancer so it is encouraging to get results. We would very much like a Scottish PCT to start a scheme but with the present uncertainty in the NHS they are reluctant to experiment with a new service.”