Original Research Article

Incidence and Risk Factors for Mild Cognitive Impairment: A Population-Based Three-Year Follow-Up Study of Cognitively Healthy Elderly Subjects
Susanna Tervo^a, Miia Kivipelto^a,d, Tuomo Hänninen^a,b, Matti Vanhanen^a, Merja Hallikainen^a, Arto Mannermaa^c, Hilkka Soininen<sup>a,b

a</sup>Department of Neuroscience and Neurology, Brain Research Unit, Clinical Research Centre, Mediteknia, University of Kuopio;
^bDepartment of Neurology, Kuopio University Hospital and
^cDepartment of Pathology, University of Kuopio, Kuopio, Finland and
^dAging Research Center, Division of Geriatric Epidemiology, Neurotec, Karolinska Institutet, Stockholm, Sweden

Address of Corresponding Author

Dement Geriatr Cogn Disord 2004;17:196-203 (DOI: 10.1159/000076356)

  Key Words

• Mild cognitive impairment
• Risk factors
• Cognitive impairment, mild

  Abstract

Background: Mild cognitive impairment (MCI) has attracted considerable interest as a potential predictor of Alzheimer's disease (AD). Both the apolipoprotein E (ApoE) 4 allele and vascular factors have been associated with a higher risk for AD, recently they have also been linked to the risk of MCI. Objectives: To estimate the incidence of MCI among cognitively healthy elderly subjects during a 3-year follow-up, and to evaluate the impact of demographic and vascular factors as well as the ApoE 4 allele on the conversion to MCI. Methods: At baseline, the cognitive abilities of 806 out of 1,150 eligible subjects (aged 60-76 years) from a population-based sample were examined. Cognitively intact subjects (n = 747) were followed for an average of 3 years. Results: 66 subjects (8.8%) had converted to MCI. The global incidence rate of MCI was 25.94/1,000 person-years. Persons with higher age (OR 1.08, 95% CI 1.01-1.16), ApoE 4 allele carriers (OR 2.04, 95% CI 1.15-3.64) and persons with medicated hypertension (OR 1.86, 95% CI 1.05-3.29) were more likely to convert to MCI than those individuals of lower age and without an ApoE 4 allele or medicated hypertension. Persons with high education (OR 0.79, 95% CI 0.70-0.89) were less likely to convert to MCI than persons with low or no education. In subjects with both the ApoE 4 allele and medicated hypertension, the crude OR for conversion was 3.92 (95% CI 1.81-8.49). In subjects with cardiovascular disease, the crude OR for conversion was 2.13 (95% CI 1.26-3.60). Gender, elevated blood pressure, diabetes or cerebrovascular disease had no significant effect on the conversion to MCI. Conclusion: Higher age, the presence of at least one ApoE 4 allele and medicated hypertension are independent risk factors, but high education is a protective factor for MCI. The results suggest that vascular factors may have an important role in the pathogenesis of MCI.

Copyright © 2004 S. Karger AG, Basel

  Author Contacts

Susanna Tervo
University of Kuopio, Brain Research Unit, Clinical Research Centre
Mediteknia, PO Box 1627
FI-70211 Kuopio (Finland)
Tel. +358 17 163520, Fax +358 17 163539, E-Mail susanna.tervo@kuh.fi

  Article Information

Accepted: August 13, 2003
Published online: January 20, 2004
Number of Print Pages : 8
Number of Figures : 1, Number of Tables : 3, Number of References : 62