Two studies assessing dementia risk in people over the age of 90 have found that developing high blood pressure at a very old age may not be a risk factor for developing the condition. The research, presented at the Alzheimer’s Association International Conference 2014, is in contrast to findings studying people at a younger age, where having high blood pressure has been found to be associated with higher risk of developing dementia.
The related findings both used participants from the 90+ Study and all volunteers were aged 90 or over at the start of the research. The volunteers were contacted by the researchers every six months for up to 10 years. One study found that those who reported as being first diagnosed with high blood pressure between the ages of 80 and 89 were less likely to develop dementia than those who had never had high blood pressure. Those who developed high blood pressure even later (over 90 years old at first diagnosis) were the least likely to develop dementia. The other, related study found, in people over 90, higher blood pressure was associated with lower risk of developing dementia. This study took into account the use of medication to lower blood pressure, which was not found to affect dementia risk.
Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“Research suggests that there is a link between blood pressure and dementia development. These studies and others highlight the complex factors that are involved in dementia risk. Evidence is showing that it is not simply that high blood pressure increases the risk of dementia, but changes to blood pressure and other factors at different stages in life may all play a part in modifying risk of the condition.
“This research is still in the early stages and as yet the underlying mechanism behind why high blood pressure appears to be protective against dementia in very late life is unclear. More research is needed to establish the exact role of blood pressure in dementia risk in different stages of life.”
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