Is diabetes linked to cognitive impairment?

World Health Matters – Germany – by Gary Finnegan: Mild cognitive impairment (MCI) is twice as common in middle-aged people with diabetes mellitus type 2, according to researchers in Essen, Germany.

However, the study, published in Journal of Alzheimer’s Disease, found an intriguing trend in older age groups: the strong association between diabetes and MCI observed in middle-aged participants (50-65 years), vanished in older participants (66-80 years).

MCI is an intermediate state between normal cognitive ageing and dementia. Although people with MCI have a higher dementia risk, very few actually develop dementia. In fact, many people with MCI convert back to a cognitively normal state.

This transitional – and therefore possibly modifiable – characteristic makes the concept of MCI a promising approach in the development of prevention strategies.

Four criteria must be met for a diagnosis of MCI. First, participants have a subjective impression of a declined cognitive performance over the last two years. Second, this subjective impression is validated in using objective measures (cognitive test battery). Third, participants are capable of handling activities of daily living. Fourth, a diagnosis of dementia is ruled out.

For this analysis, 560 participants diagnosed with MCI were compared with 1376 cognitively normal participants. Of participants with MCI, 289 had amnestic MCI and 271 had non-amnestic MCI.

Examination of differences by gender revealed a stronger association of diabetes with amnestic MCI in middle-aged women and by contrast a stronger association with non-amnestic MCI in middle-aged men.

These results suggest that middle-aged individuals with diabetes mellitus type 2 are particularly vulnerable to MCI, with gender specific effects on subtypes of MCI.

The authors of the study said this underlines the importance of high quality treatment of diabetes especially in middle age, not only because of cardiovascular damage, but also because it might help to prevent or delay cognitive decline.