News of a 43 per cent fall in stroke incidents since 2000 made headlines in October. A report from King’s College London suggested that the number of people affected by stroke is falling, but people are having strokes at a younger age.
It also reported that there has only been a small relative decrease in stroke rates in the black population. It said this may be due to higher average levels in black patients of high blood pressure and diabetes, both of which can increase the risk of stroke.
Researchers analysed data from the South London Stroke Register, looking particularly at patients who had an ischaemic stroke, which is caused by a blood clot, between 2000 and 2015.
The study also found that, across the population, patients who had strokes tended to have them younger, with a decrease in the average age at first stroke from 72.3 in 2000- 2003, to 69.3 in 2012-2015.
The team attributes the overall reduced rate to a range of factors including improved prevention measures such as medication like statins.
Reduced rates of smoking and drinking are also thought to be an important factor as making these lifestyle changes can significantly lower people’s risk of stroke.
Experienced stroke consultant Liz Iveson, based at Woodlands Neurological Centre in York, warns that headlines announcing a 43 per cent plummet in stroke numbers may be misleading.
However, she also believes the South London Stroke register from which the data was compiled, is fairly representative of the wider population.
“The lesser reduction in the black population is well known. The black population statistically has a higher incidence of hypertension and small vessel stroke and an increase in obesity.
“Overall, the incidence of ischaemic stroke has fallen but the number of people hospitalised for stroke aged between 15-44 years has risen significantly in recent years. The rates for hospitalisation for stroke in older adults have fallen. This may be in part due to increased awareness and detection of stroke in younger people too.
“There are many hypotheses and pieces of evidence around why the average age of people with stroke has fallen overall. There is an increase in stroke risk factors in the young – the number of women under 45 years old who have three to five risk factors for stroke has doubled recently.
“Rates of all the ‘traditional’ risk factors one used to associate with older age are also all increasing.
“High blood pressure and smoking are the main factors associated with the increased risk but the increase in diabetes, obesity, high cholesterol and binge drinking all contribute.”
Iveson also sees flaws in the UK’s screening system which may be contributing to a lowering of the average stroke age.
She says: “Adults under 45 don’t tend to go to screening programmes or get their blood pressure or cholesterol checked. Also, if high blood pressure is detected it is often left untreated for longer compared to older patients. The ‘go away, do some exercise, reduce stress, eat more fruit and come back approach’ is sometimes not followed up in busy individuals.
“Also, anecdotally, there is a sense that borderline high blood pressure is not acted on. Many patients I see after a stroke or mini stroke have been told for years their blood pressure is a ‘little high’ but not too bad.
“The big push is to try and emphasise that there’s no such thing as ‘borderline blood pressure’. It is either high or it isn’t. The guidelines are clear enough numbers-wise.”
Iveson also points to other risk factors such as lack of sleep and stress, which are increasingly being researched.
“People under 50 tend to work longer hours, have more perceived stress and poor sleep hygiene compared to the older population. The increase in shift working patterns and use of electronic gadgets are thought not to help with this either.
“The FAST campaign is still valid however there is some evidence that young people are less familiar with stroke symptoms and the need for urgent attention to ‘act fast’.”
The well-publicised World Stroke Day initiative on 29th October went some way to raising stroke awareness in younger people. Charities, care providers and even national governments marked the day by turning the spotlight on the issue.
From Luxembourg – where the health ministry reported the worrying fact that a quarter of all strokes there are in the under 65s – to Hyderabad, where doctors warned that one in seven stroke victims are under 45, stroke dominated headlines around the world for one day at least.
As well as greater awareness, developing better treatments is clearly key to managing stroke in all age groups.
Certainly, improved preventative measures are playing their part in lowering overall stroke numbers, says Iveson.
“There is an increased uptake in statin use and in prescribing statins. They have so much evidence behind them and the newer ones are well tolerated. Simvastatin was the main original statin but about one in five people got muscle aches and stopped the statin hence the bad press they used to have.
“But generally, I do think GPs are more aware about actively lowering cholesterol now. Statins are used so much in cardiology, diabetes, vascular and renal medicine as well as stroke, that the prescribing of them doesn’t have the same negative connotations as it used to have.”
In the longer term, inter-generational changes in drinking habits may help to limit stroke risk in younger people.
A study published in October involving nearly 10,000 young people in the UK found that the proportion of 16- to 24-year-olds who say they never drink alcohol rose from 18 per cent in 2005 to 29 per cent in 2015. The study also found that young people who did drink alcohol were drinking less nowadays and that binge drinking rates were falling.
The researchers said the drop in numbers of young people drinking suggested a shift in attitudes towards alcohol. They say this could be due to increased awareness of the health risks of alcohol, as well as changes in the way young people spend their leisure time.
The research was carried out by University College London. Iveson says: “It is really interesting thinking about the future as there is an increased trend in people aged 45-65 years drinking every day and therefore increasing their risk of stroke but there is a significant difference coming through in behaviour in the younger millennial generation.
“They are less likely to smoke, drink and take drugs and also their lifestyle choices are different. They are much more aware of healthy eating, appearance and exercise – and put it into practice. Meditation and mindfulness have been shown to reduce stroke risk and blood pressure too.
“I do think this change in lifestyle choices will have a significant impact on stroke incidence in the future. The only caution with this is again related to perceived stress and the increase in mental health issues in the younger generation. It is unclear how much this will impact.”
Meanwhile, in terms of emerging findings on stroke risk, a new study suggests that iron levels may be a factor.
Imperial College London found that people with higher iron levels may be at greater risk of certain types of stroke.
The researchers analysed genetic data from more than 48,000 people and found that higher levels of iron are associated with an elevated risk of a cardioembolic type of stroke.
A statistical method was used to calculate the impact of genetics on people’s iron status, focusing on three points in the genome where a single ‘letter’ difference in the DNA can slightly increase or reduce a person’s iron status.
These findings follow previous research which suggested that iron may protect against stroke and coronary artery disease. “This result was unexpected. It was previously thought higher iron levels might protect against stroke, but this study investigates this further to find that iron may actually increase the risk of some types of stroke,” said Dr Dipender Gill, lead author of the study.
The researchers have cautioned that this is an early stage finding and stated that they don’t recommend that patients at risk of stroke reduce their iron intake, as it has many crucial roles in the body.
Dr Gill said that further research is needed to investigate why iron may lead to increased risk of stroke. “Iron is a vital nutrient, essential for a number of biological processes in the body, including transporting oxygen.
“However, previous research has suggested that in some cases iron can actually trigger blood to form a clot. This now needs further investigation.”
In another recent stroke study, Swedish researchers have evidenced a correlation between general fitness and reduced risk of severe stroke.
The study of more than 900 stroke survivors found that fitter people were twice as likely as sedentary people to have a mild stroke rather than a severe one.
The benefit was seen among older adults who walked for an average of 35 minutes a day. “Stay physically active. Keep on walking,” advised senior researcher Dr Katharina Sunnerhagen.
The findings do not prove that exercise, itself, was responsible, said Sunnerhagen, a professor at the University of Gothenburg, in Sweden.
But she said it is clear that regular activity has a range of health benefits – and less severe strokes may be one of them.
The findings are based on data from 925 older adults treated for a stroke at the same hospital. When the patients started post- stroke rehab, they were asked about their usual exercise habits before the stroke.
Overall, 48 per cent said they’d been active. Most of the patients had suffered a mild stroke, based on tests of their movement, speech and other abilities when they were hospitalised.
But physically active people were particularly likely to have a mild stroke: 85 to 89 per cent did, versus 73 per cent of sedentary people, the findings showed.
There could, of course, be other differences between physically active and inactive seniors, Sunnerhagen said.