People living in noisy traffic areas may be 30% more likely to have a deadly stroke ‘because they’re more stressed and less likely to exercise’
- Scientists suggest it may be a lack of greenspace rather than the noise itself
- They studied 2,761 stroke victims in Spain and looked at where they lived
- A 984-foot (300m) ‘buffer’ of green space around the home cut stroke risk
People who live in noisy urban areas are more likely to have a stroke than those close to green space, according to research.
A study of more than 2,700 people in Spain found the risk of stroke rose by almost a third among people in areas with the most traffic noise.
The research couldn’t explain whether the danger came from the noise itself or whether the noise was simply a sign of living in a more polluted, less healthy area.
But the scientists suggested people living in noisy areas may be more likely to be stressed out or have high blood pressure, or be less likely to exercise.
The Barcelona researchers explained that it wasn’t clear whether traffic noise itself actually raised the risk of stroke or if the sound was just a sign of living in an area which made it more likely people would be unhealthy (stock image)
A team from Barcelona’s Hospital del Mar Medical Research Institute, Brown University in the US and other universities in Barcelona carried out the study.
They used medical records and address details of 2,761 stroke patients from between 2005 and 2014 in the city.
Living surrounded by a high average level of noise pollution raised the risk of severe stroke by 30 per cent.
A severe stroke was defined loosely as one which caused more than two noticeable symptoms, such as difficulty moving or speaking normally, reduced consciousness or memory issues.
More than 100,000 strokes happen every year in the UK and there are around 1.2million stroke survivors alive today, but it is a leading cause of death.
WHAT IS A STROKE?
There are two kinds of stroke:
1. ISCHEMIC STROKE
An ischemic stroke – which accounts for 80 percent of strokes – occurs when there is a blockage in a blood vessel that prevents blood from reaching part of the brain.
2. HEMORRHAGIC STROKE
The more rare, a hemorrhagic stroke, occurs when a blood vessel bursts, flooding part of the brain with too much blood while depriving other areas of adequate blood supply.
It can be the result of an AVM, or arteriovenous malformation (an abnormal cluster of blood vessels), in the brain.
Thirty percent of subarachnoid hemorrhage sufferers die before reaching the hospital. A further 25 percent die within 24 hours. And 40 percent of survivors die within a week.
Age, high blood pressure, smoking, obesity, sedentary lifestyle, diabetes, atrial fibrillation, family history, and history of a previous stroke or TIA are all risk factors for having a stroke.
SYMPTOMS OF A STROKE
- Sudden numbness or weakness of the face, arm or leg, especially on one side of the body
- Sudden confusion, trouble speaking or understanding
- Sudden trouble seeing or blurred vision in one or both eyes
- Sudden trouble walking, dizziness, loss of balance or coordination
- Sudden severe headache with no known cause
Of the roughly three out of four people who survive a stroke, many will have life-long disabilities.
This includes difficulty walking, communicating, eating, and completing everyday tasks or chores.
Both are potentially fatal, and patients require surgery or a drug called tPA (tissue plasminogen activator) within three hours to save them.
In the US, about 795,000 people have strokes annually and some 140,000 of them die – about one out of every 20 deaths is caused by stroke.
As well as a link between stroke and traffic noise in the neighbourhood, the Barcelona researchers also found green space around the home played a part.
People living with at least 984 feet (300m) of green space around their street had a 25 per cent lower chance of suffering a severe stroke than those who didn’t.
The risks were relative, meaning someone in a noisy area didn’t have a one-in-three chance of having a stroke, just a 30 per cent higher risk than someone in a quiet area (for example, a rise from one in 10,000 risk to 1.3 in 10,000).
In their paper the researchers, led by Dr Rosa Vivanco-Hidalgo, couldn’t explain how noise pollution may raise the risk of a stroke.
They said: ‘Road traffic noise has also been related with adverse [heart] outcomes, but few studies have assessed the influence on stroke, suggesting that traffic noise might play a [harmful] role increasing its risk.
‘There are no studies, though, testing specifically its effect in acute ischemic stroke severity.
‘A possible mechanism that could explain the association is that noise may also lead to endothelial dysfunction and arterial hypertension.’
Endothelial dysfunction is the failure of cells inside the blood vessels to work properly, while arterial hypertension is high blood pressure.
Damage to the insides of blood vessels – such as that caused by high blood pressure – can lead to stroke by making it more likely a blood clot will develop.
This clot can then break loose and travel through the bloodstream to the head or neck, where it may block the flow of blood and oxygen to the brain.
Another possibility raised in the study was that the traffic noise was simply a sign of someone living in an urban area without much green space.
Dr Vivanco-Hidalgo and her team suggested being closer to green space might help people be less stressed, more physically active and develop healthier immune systems and circulation.
They didn’t find a link between the levels of certain types of pollution – PM2.5 – and how severe someone’s stroke was.
The research was published in the journal Environmental Research.
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