The research, led by a team at Johns Hopkins University in Baltimore, looked at data from the 20-year Atherosclerosis Risk in Communities Study. They included data on 13,351 people who were aged between 48 and 67 in 1990, when each participant took part in a series of cognitive tests to assess their thinking and memory. These tests were repeated after six years, and again around 20 years after the first tests were carried out. When the study began, the participants were also asked if they had been diagnosed with diabetes, and their blood sugar levels were checked for signs of the condition.
The researchers found that those who had diabetes or higher blood sugar levels in midlife tended to have worse cognitive scores after 20 years than people without the condition. Further analysis showed that diabetic people with the highest blood sugar levels had the greatest decline in thinking and memory over two decades.
Dr Laura Phipps of Alzheimer’s Research UK, the UK’s leading dementia research charity, said: “This study adds to a large body of evidence linking diabetes to thinking and memory problems in later life, and suggests that controlling blood sugar levels in midlife may also have long-term benefits for our brain health.
“Although this research did not look at dementia, understanding how to keep our brains healthy as we grow older could provide vital insight to help efforts to prevent the condition. The mechanisms underlying the links between diabetes, cognitive decline and dementia are still not fully understood, and further research is needed to shed light on this topic.
“Investment in research is crucial to gain a full understanding of the risk factors for dementia and find ways to prevent the condition. Though we don’t yet have a sure-fire way to stave off the condition, we do know that risk factors for diabetes can also be risk factors for dementia. Evidence suggests we can lower our risk of dementia by keeping healthy: eating a balanced diet, exercising regularly, not smoking, and keeping blood pressure and weight in check.”
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