Fewer now dying from strokes, but numbers having the...

"Stroke deaths in England halved in a decade," reports The Guardian, but the Sun warns us that, "Stroke rates are rocketing among young Brits due to obesity and cocaine use".

Both headlines were prompted by a new study where researchers looked at NHS stroke data from between 2001 and 2010.

They found the number of people in England dying from stroke fell sharply during this time, with drops each year of about 6%.

A stroke happens when the brain is damaged by an interruption of blood supply. This can be the result of a clot blocking a blood vessel or bleeding in the brain.

Depending on how bad the damage to the brain is, stroke can be fatal or cause lasting disability.

A reduction in deaths from stroke could be because fewer people are having strokes, or because more people are surviving them.

The researchers' analysis showed most of the reduction in stroke deaths came from more people surviving strokes, possibly because of better stroke care.

But while the number of stroke deaths fell among older age groups, there was a worrying increase in people aged 35 to 54 who had strokes, at a rate of around 2% more each year.

Researchers say increased levels of obesity could be behind the rise.

The best way to help prevent a stroke is to eat a healthy diet, exercise regularly, and avoid smoking and drinking too much alcohol.

Find out more about how to prevent a stroke

Where did the story come from?

The researchers who carried out the study were from the University of Oxford.

Although the study had no specific funding, the researchers were supported by the National Institute for Health Research, the Oxford Biomedical Research Centre, the UK Medical Research Council, the British Heart Foundation and the Wellcome Trust.

It was published in the peer-reviewed British Medical Journal on an open access basis, so you can read the study for free online.

The study was widely covered in the UK media, with most stories appearing accurate and balanced.

Some focused on the good news (such as The Guardian, The Independent and The Times), with headlines about the fall in stroke deaths.

Others (the Sun and The Daily Telegraph) were more interested in the rise in stroke among younger people. The Mail Online balanced positive and negative in its coverage.

The Sun's headline that, "Stroke rates are rocketing among young Brits due to obesity and cocaine use," is arguably sensationalist.

While a 2% rise in stroke rates in younger people is unwelcome, it could hardly be described as "rocketing".

And there's no evidence presented in the study that cocaine use was partly responsible for this rise.

What kind of research was this?

This was a database study using NHS data on hospital admissions for stroke, along with mortality data showing how many people died from stroke.

This type of study is useful for understanding trends in data over time, although it cannot tell us whether any particular aspect (such as specific changes to stroke care or changing obesity levels) are responsible for these trends.

What did the research involve?

Researchers used NHS England's Hospital Episode Statistics data to find all admissions to hospital for stroke and the Office for National Statistics' mortality data, which records how many people die each year and their cause of death.

They found:

how many people had a stroke each year from 2001 to 2010
how many people who had a stroke died of it within 30 days
how many people died of a stroke each year

Researchers analysed these 3 figures in a mathematical model to calculate how important each of the first 2 were in determining the third.

In other words, how much of the change over time in people dying from stroke was because of changes in the numbers having a stroke, and how much was the result of changes in stroke survival.

They presented results separately for men and women and for different age groups.

What were the basic results?

Researchers found information about 947,497 strokes between 2001 and 2010, resulting in 337,085 deaths. About 35.5% of people who had a stroke died.

The total number of deaths from stroke decreased in men and women over the decade, with 15,253 fewer stroke deaths in 2001 than 2010:

the number of men dying from stroke almost halved from 140 for every 100,000 people in 2001 to 74 per 100,000 in 2010
the number of women dying from stroke fell from 128 for every 100,000 people in 2001 to 72 per 100,000 in 2010

Overall, this reflected about a 6% decline in mortality for men and women each year, though the greatest decline was in the 65 to 74 age group, with an 8% decline each year.

The total number of strokes decreased, but this was mainly in older age groups:

the number of men having strokes fell from 345 per 100,000 in 2001 to 285 per 100,000 in 2010
the number of women having strokes fell from 280 per 100,000 in 2001 to 234 per 100,000 in 2010

Overall, this represented an annual decline in stroke rates of 1.3% for men and 2.1% for women, though again the reduction in strokes was largest in older age groups.

For example, in the over-85 age group it fell by 2.7% for women and 3.4% for men each year.

Meanwhile, stroke rates among people aged 35 to 54 rose by 2.1% for women and 2.2% for men each year from 2001 to 2010.

People who had strokes were much more likely to survive them by the end of the decade.

When looking at the number of people who died within the first 30 days of a stroke:

41.8% of men who had a stroke in 2001 died, compared with 26.4% who had a stroke in 2010
44.1% of women who had a stroke in 2001 died, compared with 28.5% who had a stroke in 2010

The results showed 71% of the overall reduction in deaths from stroke across the decade was down to fewer people who had a stroke dying from it, while 29% of the reduction was the result of fewer people having strokes.

How did the researchers interpret the results?

The researchers said the "marked decline" in stroke mortality rates "has been the result of improved survival of patients with stroke more than a decrease in event rates [number of strokes]".

They said analysis of the figures by age highlighted the rise in strokes among younger groups, suggesting that "although prevention was effective in reducing stroke event rates in older people, it failed in the young".

They added: "To reduce the burden of stroke care on hospitals and decrease the dependence on emergency services, prevention of vascular events needs to be strengthened."

Conclusion

Clearly it's good news that more people are surviving stroke and fewer people are dying from it. But the finding that younger people are having more strokes is a concern.

We cannot tell from the study what's behind the improved survival rates for stroke.

But the NHS introduced many changes to stroke care during this period, including specialist stroke units in all hospitals taking stroke patients, better access to brain scans and improved use of medication for acute strokes.

There was also the introduction of the "Act FAST" campaign by Public Health England during this time. This campaign was designed to increase awareness among the general public of the need to act fast and call an ambulance if they suspect a stroke.

These both might be contributing factors.

The study showed the overall decline in the number of people having strokes was modest and dependent on age.

The older age group from about 65 upwards were having fewer strokes by 2010 than in 2001. By contrast, the 35 to 54 age group had more strokes by the end of the decade than the start.

It's difficult to know for sure why this pattern was seen. It could be that, among older age groups, improvements in the overall care and diagnosis of chronic conditions like high blood pressure and cholesterol have decreased their risk of stroke.

Meanwhile, changes in population health, such as growing rates of obesity, could have increased cardiovascular risk among younger people. They could be less likely to be brought to medical attention or receive preventative medicines, for example.

This is speculation, but the results suggest younger people and their doctors may need to think more about their risk of stroke to avoid reversing some of the progress that's been made.

The study data only applies to England and we do not know whether the same pattern would be seen in Scotland, Wales or Northern Ireland.

The data set is also in itself quite outdated now, representing 2001 to 2010. It would be interesting to see how things may have changed over the past decade.