Cognitive dysfunction in adults with type 1 (insulin-dependent) diabetes mellitus of long duration: effects of recurrent hypoglycaemia and other chronic complications.
To examine the long-term effects of recurrent severe hypoglycaemia and other biomedical complications on mental efficiency, a battery of cognitive tests was administered to 142 Type 1 (insulin-dependent) diabetic adult patients (age 33.5 +/- 5.6 years; mean +/- SD) and 100 demographically similar non-diabetic control subjects. All diabetic subjects had been diagnosed before the age of 17 years. Diabetic subjects with one or more complications (distal symmetrical polyneuropathy; advanced background or proliferative retinopathy; overt nephropathy; one or more episodes of severe hypoglycaemia) performed significantly (p < 0.001) more poorly than non-diabetic control subjects on tests requiring sustained attention, rapid analysis of visuospatial detail, and hand eye co-ordination. Regression analyses indicated that the best biomedical predictor of cognitive test performance was a diagnosis of polyneuropathy. Although severe recurrent hypoglycaemia was not associated with performance on any test, the neuropathy x recurrent hypoglycaemia interaction term was significant. These results suggest that in adults with Type 1 diabetes of long duration, recurrent hypoglycaemia does not appear to influence cognitive performance directly, but may interact with neuropathy to exaggerate or otherwise magnify the extent of neurobehavioural dysfunction.
Ryan
C M
CM
Department of Psychiatry, University of Pittsburgh, School of Medicine, Pennsylvania.
Williams
T M
TM
Finegold
D N
DN
Orchard
T J
TJ
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D003072:Cognition Disorders / Q000209:etiology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology* / Q000523:psychology*; D003929:Diabetic Neuropathies / Q000503:physiopathology / Q000523:psychology*; D003930:Diabetic Retinopathy / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology / Q000503:physiopathology / Q000523:psychology*; D007361:Intelligence Tests; D008297:Male; D009483:Neuropsychological Tests
D001786:Blood Glucose; D006442:Glycated Hemoglobin