Cognition in the Early Stage of Type 2 Diabetes
- Carla Ruis, MSC,1,
- Geert Jan Biessels, PHD1,
- Kees J. Gorter, PHD2,
- Maureen van den Donk, PHD2,
- L. Jaap Kappelle, PHD1 and
- Guy E.H.M. Rutten, PHD2
- 1Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, the Netherlands;
- 2Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, the Netherlands.
- Corresponding author: Carla Ruis, c.ruis{at}umcutrecht.nl.
Abstract
OBJECTIVE Type 2 diabetes is known to be associated with decrements in memory and executive functions and information-processing speed. It is less clear, however, at which stage of diabetes these cognitive decrements develop and how they progress over time. In this study, we investigated cognitive functioning of patients with recent screen-detected type 2 diabetes, thus providing insight into the nature and severity of cognitive decrements in the early stage of the disease. Possible risk factors were also addressed.
RESEARCH DESIGN AND METHODS Included in this study were 183 diabetic patients from a previously established study cohort and 69 control subjects. A full neuropsychological assessment, addressing six cognitive domains, was made for each participant. Raw test scores were standardized into z scores per domain and compared between the groups. Possible risk factors for cognitive decrements were examined with multivariate linear regression.
RESULTS Relative to scores for the control group, mean z scores were between 0.01 and 0.2 lower in the diabetic group across all domains, but after adjustment for differences in IQ between patients and control subjects, only memory performance was significantly reduced (mean difference −0.15 [95% CI −0.28 to −0.03]). A history of macrovascular disease and current smoking were significant determinants of slower information-processing speed in patients with diabetes.
CONCLUSIONS This study shows that modest cognitive decrements are already present at the early stage of type 2 diabetes. A history of macrovascular disease and smoking are significant risk factors for some early decrements.
Footnotes
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The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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- Received December 8, 2008.
- Accepted March 25, 2009.
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Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. See http://creativecommons.org/licenses/by-nc-nd/3.0/ for details.
- © 2009 by the American Diabetes Association.
