A study recently conducted by The University of Exeter Medical School analyzed the data on stroke and dementia risk from 3.2 million individuals around the world. The data revealed that the link between stroke and dementia persisted even after taking into effect factors such as blood pressure, diabetes and cardiovascular disease. These findings from the largest study of its kind provide the strongest evidence yet that having a stroke significantly increases the risk of dementia. Previously, it has been established that there was a link between stroke and dementia and this study sought to build upon this connection.
“We found that a history of stroke increases dementia risk by around 70%, and recent strokes more than doubled the risk,” said Dr Ilianna Lourida, of the University of Exeter Medical School. “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.” According to The World Health Organisation, 15 million people have a stroke each year. Moreover, it is estimated that 50 million people globally are suffering from dementia — a number expected to double over the next 20 years, reaching 131 million by 2050. The location of the stroke and extent of brain damage that it causes may help to explain variation in dementia risk observed between studies. Additionally, results suggested that dementia risk may be higher for men following stroke. Further research is required to clarify whether factors such as ethnicity and education affect dementia risk following stroke. Most people who have a stroke do not go on to develop dementia, so further research is also needed to establish whether differences in post-stroke care and lifestyle can reduce the risk of dementia further. “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,” concluded Dr David Llewellyn, from the University of Exeter Medical School. “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.”