Midlife-onset diabetes may lead to brain atrophy, cognitive impairment

Midlife onset of diabetes was strongly correlated with loss of brain volume and cognitive impairment later in life, according to recent research.

Researchers studied data from 1,437 participants (median age, 80 years) in Olmsted County, Minn., who were evaluated by clinical professionals and underwent extensive neuropsychological testing. An expert panel evaluated the participants and classified them as cognitively normal, possessing mild cognitive impairment or dementia. The reference group consisted of participants without diabetes or hypertension.

Midlife onset of diabetes (at age 40 to 60 years) was associated with subcortical infarctions (OR=1.85; 95% CI, 1.09-3.15), a reduction of hippocampal volume by 4% on average (95% CI, –7 to –1), reduced whole brain volume of 2.9% on average (95% CI, –4.1 to –1.6) and mild cognitive impairment (OR=2.08; P=.01). After adjusting for infarctions and white matter hyperintensity volume, the association between mild cognitive impairment and diabetes remained strong; however, the association diminished after adjusting for whole brain volume (OR=1.6; 95% CI, 0.87-2.95). Midlife onset of hypertension was associated with infarctions and white matter hyperintensity, but was only nominally associated with impaired executive function.

"People who developed diabetes even in old age were also more likely to have areas of brain damage. Conversely, there were not many effects from high blood pressure that developed in old age," Rosebud O. Roberts, MBChB, of the Mayo Clinic in Rochester, Minn., said in a press release. "Overall, our findings suggest that the effects of these diseases on the brain take decades to develop and show up as brain damage and lead to symptoms that affect their memory and other thinking skills. In particular, diabetes has adverse effects regardless of the age at which diabetes develops."

According to the research, the findings suggest that the loss in brain volume in patients with diabetes may help to explain the higher prevalence of Alzheimer’s disease among those with diabetes.

"Potentially, if we can prevent or control diabetes and high blood pressure in middle age, we can prevent or delay the brain damage that occurs decades later and leads to memory and thinking problems and dementia," Roberts said.

Disclosure: Roberts receives research support from AbbVie. See the study for a list of the researchers’ financial disclosures.