Central nervous system function in youth with type 1 diabetes 12 years after disease onset.
OBJECTIVE
In this study, we used neurocognitive assessment and neuroimaging to examine brain function in youth with type 1 diabetes studied prospectively from diagnosis.


METHODS
We studied type 1 diabetic (n = 106) and control subjects (n = 75) with no significant group difference on IQ at baseline 12 years previously by using the Wechsler Abbreviated Scale of General Intelligence, magnetic resonance spectroscopy and imaging, and metabolic control data from diagnosis.


RESULTS
Type 1 diabetic subjects had lower verbal and full scale IQs than control subjects (both P < 0.05). Type 1 diabetic subjects had lower N-acetylaspartate in frontal lobes and basal ganglia and higher myoinositol and choline in frontal and temporal lobes and basal ganglia than control subjects (all P < 0.05). Type 1 diabetic subjects, relative to control subjects, had decreased gray matter in bilateral thalami and right parahippocampal gyrus and insular cortex. White matter was decreased in bilateral parahippocampi, left temporal lobe, and middle frontal area (all P < 0.0005 uncorrected). T2 in type 1 diabetic subjects was increased in left superior temporal gyrus and decreased in bilateral lentiform nuclei, caudate nuclei and thalami, and right insular area (all P < 0.0005 uncorrected). Early-onset disease predicted lower performance IQ, and hypoglycemia was associated with lower verbal IQ and volume reduction in thalamus; poor metabolic control predicted elevated myoinositol and decreased T2 in thalamus; and older age predicted volume loss and T2 change in basal ganglia.


CONCLUSIONS
This study documents brain effects 12 years after diagnosis in a type 1 diabetic sample whose IQ at diagnosis matched that of control subjects. Findings suggest several neuropathological processes including gliosis, demyelination, and altered osmolarity.
Northam
Elisabeth A
EA
Department of Psychology, Royal Children's Hospital, University of Melbourne, Melbourne, Australia. lis.northam@rch.org.au
Rankins
Debbie
D
Lin
Ashleigh
A
Wellard
R Mark
RM
Pell
Gaby S
GS
Finch
Sue J
SJ
Werther
George A
GA
Cameron
Fergus J
FJ
D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology*; D016022:Case-Control Studies; D003922:Diabetes Mellitus, Type 1 / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013788:Thalamus / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology; D013997:Time Factors; D055815:Young Adult