A US study has shown people who develop type 2 diabetes in middle age may be more likely to have smaller brain volumes and memory problems later in life. The research is published on Wednesday 19 March in the journal Neurology online.
Researchers at the Mayo Clinic, in Rochester, used medical records, brain scans and cognitive tests to evaluate 1,437 people aged between 70 and 89, who were enrolled in the Mayo Clinic Study of Aging. The participants were grouped into different categories based on their medical records:
• people who had developed type 2 diabetes or high blood pressure in midlife (between the ages of 40 and 64)
• people who developed either condition in later life, after the age of 65
• people who had never had type 2 diabetes or dementia.
Each participant underwent a series of cognitive tests to assess their memory and thinking skills, with the results showing that 228 people had mild cognitive impairment (MCI) – memory problems not severe enough to be classed as dementia – while the rest of the group had no memory problems. The researchers also used MRI scans to measure brain volume and look for markers of damage that have been linked to dementia.
The results showed that those who had developed diabetes in midlife were more likely to have MCI than those who developed the disease later in life, or not at all. Further analysis showed that people who developed diabetes in midlife also tended to have smaller brain volumes than those without diabetes, or who developed the disease later. Meanwhile people who had high blood pressure in midlife were slightly more likely to have other markers of damage in the brain than those whose blood pressure was high later in life. The researchers argue that the age at which these conditions develop could have an impact on the brain in later life.
Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:
“Previous research has linked type 2 diabetes and high blood pressure to an increased risk of dementia, but the reasons underlying these links are not yet fully understood. It’s not possible to know from this study whether type 2 diabetes or high blood pressure cause dementia, and more research is needed to gain a full understanding of their impact on the brain. This research did not involve people with dementia, but the mild memory problems explored here can be a precursor to dementia, and understanding why some people go on to develop the condition while others do not could help prevention efforts.
“There are many reasons to keep healthy in middle age, and other research has previously suggested that our health in midlife can affect our risk of cognitive decline and dementia in later life. Continued investment in research is important to better understand the different factors that can affect our risk of dementia and the ways it might be prevented. In the meantime, other evidence shows we can lower our risk by eating a healthy, balanced diet, not smoking, taking regular exercise, keeping weight in check and controlling blood pressure.”