“Our research shows a possible link between higher blood sugar levels -- a state often described as ‘prediabetes’ -- and higher risks of cognitive decline and vascular dementia,” said researcher Dr. Victoria Garfield. “As an observational study, it cannot prove high blood sugar levels cause worsening brain health. However, we believe there is a potential connection that needs to be investigated further.”
The link between blood sugar and brain function
For the study, the researchers analyzed data from individuals involved in the U.K. Biobank dataset. All of the participants received MRI brain scans, regular blood work to measure their blood sugar levels, and cognitive assessments. With all of this information, the researchers worked to determine what effect blood sugar has on brain function.
The researchers found that brain health worsened over time among the participants with the highest blood sugar levels. Findings showed that these participants were at an increased risk of developing vascular dementia and were over 40 percent more likely to experience mild cognitive decline.
“Previous research has found a link between poorer cognitive outcomes and diabetes, but our study is the first to investigate how having high blood sugar levels that are relatively high -- but do not yet constitute diabetes -- may affect our brain health,” Dr. Garfield said.
The study showed that participants who had been diagnosed with diabetes had a similar rate of cognitive decline as participants with prediabetes. However, the risk of dementia was three times higher for participants with diabetes. While there was no increased risk of Alzheimer’s for participants with prediabetes, the researchers found that progressing to diabetes also increased the risk of this condition.
Staying healthy into old age
Moving forward, the researchers hope that more work is done to better understand the relationship with prediabetes and brain function. They said that better prevention strategies could be used to lower the number of prediabetes cases and help consumers protect their brain health into older age.
“In this relatively young age group, the risks of cognitive decline and of dementia are very low; the excess risks we observe in relation to elevated blood sugar only modestly increase the absolute rates of ill health,” said researcher Nishi Chaturvedi. “Seeing whether these effects persist as people get older, and where absolute rates of disease get higher, will be important.