Diabetes is a known risk factor for cognitive decline and dementia, age-related conditions that affect memory and thinking skills. However, little is known about how the diabetes-cognitive decline link compares across cultures.

Scientists from Mayo Clinic and Huashan Hospital in Shanghai explored the association between Type 2 diabetes and cognitive impairment to find out if the relationship varies in different populations. The scientists analyzed medical data from 3,348 Chinese adults and 3,734 American adults, all of whom had undergone cognitive testing and were dementia-free.

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The researchers found that all of the participants who had Type 2 diabetes performed significantly worse on cognitive tests, compared to participants who did not have diabetes.

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"We wanted to study diabetes and cognitive impairment in these two completely different ethnic groups to see whether there are any differences. We found that in both cohorts, having a history of diabetes was associated with greater impairment in cognitive function," says study co-author Rosebud Roberts, an epidemiologist at Mayo Clinic.

The results were the same -- even after adjusting for age, gender and education, as well as vascular problems. More specifically, the American and Chinese study participants with diabetes performed considerably worse on executive function tests, compared to people in both study populations who did not have diabetes. Executive function is the ability to make decisions, plan and problem-solve, and is associated with the frontal lobe of the brain.

Roberts says the research is important, because it shows that impairment in executive function may be an early effect of diabetes, and earlier age at diabetes diagnosis results in greater cognitive deficits. -- Mayo Clinic News Network