Health In Focus
  • The most extensive study of its kind has found that stroke increases dementia risk to a great extent
  • Recent stroke doubled dementia risk whereas a history of stroke increased dementia risk by around 70 percent
  • Dementia is present in around 50 million people globally, and is expected to double over 20 years, reaching 131 million by 2050
  • Improvements in stroke prevention and post-stroke care may play a key role in dementia prevention

Having a stroke doubles the risk of developing dementia, according to the most extensive study conducted in this field.

The new research has been published in the leading dementia journal Alzheimer's & Dementia: The Journal of the Alzheimer's Association and is the first meta-analysis in the area.
Stroke Doubles Risk of Dementia

This analysis of stroke and dementia risk was conducted on 3.2 million people across the world by a team of researchers from the University of Exeter Medical. The results showed that there was a clear association between stroke and dementia even after taking into account other dementia risk factors of health like blood pressure, diabetes and cardiovascular disease.

Stroke and dementia have been linked in earlier studies though the precise degree to which stroke increased dementia risk had not been measured. The current study chose to analyze this association.

Link between Stroke and Dementia

The research team analyzed 36 studies and found that about 1.9 million people who participated in these studies had a history of stroke. They further analyzed 12 studies, which added to the total number by another 1.3 million people - the studies had looked at whether participants had a recent stroke over the study period. The findings were -
  • A history of stroke increases the risk of dementia by around 70 perecent
  • Recent strokes more than doubled the risk of dementia"
Dr Ilianna Lourida, of the University of Exeter Medical School, said: "Given how common both stroke and dementia are, this strong link is an important finding. Improvements in stroke prevention and post-stroke care may therefore play a key role in dementia prevention."
  • Every year, about 15 million people suffer a stroke, according to the World Health Organization
  • Dementia is present in around 50 million people globally, and this number is expected almost to double over 20 years, reaching 131 million by 2050
The variation in dementia risk observed between studies could be because of stroke characteristics such as the location and extent of brain damage. It is also possible that dementia is higher for men following a stroke.

Authors say that since most people who had a stroke do not go on to develop dementia, further research might need to be done to clarify whether the care people get post-stroke and the lifestyle they lead might reduce the risk of dementia further. They also need research on whether factors like ethnicity and education could modify the risk.

Dr David Llewellyn, from the University of Exeter Medical School, concluded: "Around a third of dementia cases are thought to be potentially preventable, though this estimate does not take into account the risk associated with stroke. Our findings indicate that this figure could be even higher, and reinforce the importance of protecting the blood supply to the brain when attempting to reduce the global burden of dementia."

The findings of the current study give one of the strongest pieces of evidence until now that having a stroke significantly increases the risk of dementia.

Reference :
  1. Stroke doubles dementia risk, concludes large-scale study
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Source: Medindia

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