Hippocampal damage and memory impairments as possible early brain complications of type 2 diabetes.
OBJECTIVE
There is evidence that type 2 diabetes mellitus is associated with cognitive impairment. Most studies investigating this association have evaluated elderly individuals, after many years of diabetes, who generally have poor glycaemic control and significant vascular disease. The aim of the current study was to investigate the early cognitive consequences and associated brain correlates of type 2 diabetes.


METHODS
With regard to cognition and brain measures, we compared 23 age-, sex- and education-matched control subjects with 23 mostly middle-aged individuals with relatively well-controlled diabetes of less than 10 years from the time of diagnosis.


RESULTS
We found deficits in hippocampal-based memory performance and preservation of other cognitive domains. Relative to control subjects, individuals with diabetes had reductions in brain volumes that were restricted to the hippocampus. There was an inverse relationship between glycaemic control and hippocampal volume; in multivariate regression analysis, HbA(1c) was the only significant predictor of hippocampal volume, accounting for 33% of the observed variance. Other variables commonly associated with type 2 diabetes, such as elevated BMI, hypertension or dyslipidaemia, did not independently contribute to the variance in hippocampal volume.


CONCLUSIONS
These results suggest that the medial temporal lobe may be the first brain site affected by type 2 diabetes and that individuals in poorer metabolic control may be affected to a greater extent.
Gold
S M
SM
Department of Psychiatry, New York University School of Medicine, 550 First Avenue, HN-400, New York, NY 10016, USA.
Dziobek
I
I
Sweat
V
V
Tirsi
A
A
Rogers
K
K
Bruehl
H
H
Tsui
W
W
Richardson
S
S
Javier
E
E
Convit
A
A
D000368:Aged; D001921:Brain / Q000473:pathology; D001927:Brain Diseases / Q000150:complications*; D003071:Cognition; D048909:Diabetes Complications / Q000175:diagnosis*; D003924:Diabetes Mellitus, Type 2 / Q000473:pathology*; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000150:complications*; D008875:Middle Aged; D009483:Neuropsychological Tests