title: Severe hypoglycemia and intelligence in adult patients with insulin-treated diabetes.
abstract: The IQ scores (WAIS-R) of 100 patients with insulin-treated diabetes (aged 25-52 yr) were compared with those of 100 healthy control subjects who were matched to the diabetic patients for sex, age, education, and social class. The diabetic group had lower WAIS-R performance and verbal IQ scores than the control group (P = 0.017 and P = 0.033, respectively) after controlling for premorbid IQ. The extent of the difference was modest, representing approximately 33% of an SD in IQ. When frequency of severe hypoglycemia was controlled for the difference in performance IQ between the diabetic patient group and the control group was abolished, whereas the difference between the groups in verbal IQ persisted. It is hypothesised that cumulative severe hypoglycemia might be the major factor in the slight performance IQ differences between diabetic patients and control subjects. The origin of the verbal IQ differences, although obscure, might be related to the social impact of the disorder.
authors.affiliation: Department of Psychology, University of Edinburgh, UK.
authors.forename: I J
authors.initials: IJ
authors.lastname: Deary
authors.forename: J R
authors.initials: JR
authors.lastname: Crawford
authors.forename: D A
authors.initials: DA
authors.lastname: Hepburn
authors.forename: S J
authors.initials: SJ
authors.lastname: Langan
authors.forename: L M
authors.initials: LM
authors.lastname: Blackmore
authors.forename: B M
authors.initials: BM
authors.lastname: Frier
mesh_terms: D000328:Adult; D003071:Cognition; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000523:psychology*; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology / Q000523:psychology*; D007361:Intelligence Tests; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011932:Reading; D012016:Reference Values; D014888:Wechsler Scales