Editors' ChoiceNEUROLOGY and METABOLISM

Diabetes Shrinks the Brain

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Science Translational Medicine  04 Dec 2013:
Vol. 5, Issue 214, pp. 214ec199
DOI: 10.1126/scitranslmed.3008073

Infamous complications of type 2 diabetes (T2D) include hypertension, nephropathy, and retinopathy, but does this increasingly common disorder also contribute to loss of brain volume and cognitive decline? With more than 1 in 10 adults in the United States with diabetes and our current aging population, this pressing question must be addressed. Now, Moran et al. investigate which brain regions atrophy in the setting of T2D and whether a link exists between the observed neural changes and cognitive decline.

In a cross-sectional study, 350 individuals with T2D (mean age 67.8 years) and 363 control subjects (mean age 72.2 years) underwent magnetic resonance imaging (MRI) brain scans and cognitive assessments. After adjusting for age, sex, and total intracranial volume, the individuals with T2D were found to have lower total gray matter, lower white matter, and lower hippocampal volume as well as more cerebral infarcts. In addition, individuals with T2D scored worse on certain cognitive tasks, and a longer duration of diabetes was associated with poorer scores. Further statistical analyses revealed that the lower cognitive scores were related to lower brain volumes rather than with cerebral infarcts. The authors conclude that brain atrophy, rather than cerebrovascular lesions, mediates the relationship between diabetes and cognitive decline.

The authors suggest that the changes observed in individuals with T2D are similar to those observed in patients with early Alzheimer’s disease, but further studies are needed to explore this conclusion. This large-cohort neuroimaging study underscores the need for researchers to decipher mechanisms that underlie neural and cognitive alterations in diabetes in order to find ways to prevent progression to dementia in this high-risk population. In the meantime, preventing diabetes may be our best bet in stemming cognitive decline.

C. Moran et al., Brain atrophy in type 2 diabetes: Regional distribution and influence on cognition. Diabetes Care 36, 4036–4042 (2013). [Full Text]

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