Elsevier

The Lancet Neurology

Volume 5, Issue 9, September 2006, Pages 735-741
The Lancet Neurology

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Risk score for the prediction of dementia risk in 20 years among middle aged people: a longitudinal, population-based study

https://doi.org/10.1016/S1474-4422(06)70537-3Get rights and content

Summary

Background

Several vascular risk factors are associated with dementia. We sought to develop a simple method for the prediction of the risk of late-life dementia in people of middle age on the basis of their risk profiles.

Methods

Data were used from the population-based CAIDE study, which included 1409 individuals who were studied in midlife and re-examined 20 years later for signs of dementia. Several midlife vascular risk factors were studied to create the scoring tool. The score values were estimated on the basis of β coefficients and the dementia risk score was the sum of these individual scores (range 0–15).

Findings

Occurrence of dementia during the 20 years of follow-up was 4%. Future dementia was significantly predicted by high age (≥47 years), low education (<10 years), hypertension, hypercholesterolaemia, and obesity. The dementia risk score predicted dementia well (area under curve 0·77; 95% CI 0·71–0·83). The risk of dementia according to the categories of the dementia risk score was 1·0% for those with a score of 0–5, 1·9% for a score of 6–7, 4·2% for a score of 8–9, 7·4% for a score of 10–11, and 16·4% for a score of 12–15. When the cut-off of 9 points or more was applied the sensitivity was 0·77, the specificity was 0·63, and the negative predictive value was 0·98.

Interpretation

The dementia risk score is a novel approach for the prediction of dementia risk, but should be validated and further improved to increase its predictive value. This approach highlights the role of vascular factors in the development of dementia and could help to identify individuals who might benefit from intensive lifestyle consultations and pharmacological interventions.

Introduction

The occurrence of dementia is rising substantially worldwide.1, 2, 3 No curative treatment is available and extensive efforts for the prevention of dementia are needed. Identification of individuals at increased risk of dementia would allow more efficient targeting of available preventive measures than currently possible.

Risk scores have been developed to predict the risk of cardiovascular events, diabetes, and mortality.4, 5, 6, 7, 8, 9, 10, 11 Risk scores have generally included only a few known risk factors that are easily measurable to calculate the subsequent risk of an event or disease within a given time frame. Although the absolute risk of an event might differ across populations, risk ranking by use of risk scores is consistent.12, 13, 14, 15 The main use of risk scores is for targeting of preventive measures to those most at risk of the disease.16 Another important benefit is that they can be used to distribute easily understandable information about risk factors to the general population.

Dementia shares many risk factors with cardiovascular diseases, including hypertension, hypercholesterolaemia, obesity, and diabetes.17, 18, 19, 20, 21, 22 Risk scores have not yet been developed to predict the risk of dementia. The aim of this study was to develop a model for a simple technique to predict the late risk of dementia on the basis of risk factor profiles present in middle age using data from the population-based Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) study.23

Section snippets

Participants

The participants of the CAIDE study were derived from four separate and independent population-based random samples examined within the framework of the North Karelia Project and the FINMONICA study in 1972, 1977, 1982, or 1987.24, 25, 26 Participation rates of these surveys ranged from 82% to 90%. Those individuals still alive who were aged 65–79 years at the end of 1997 and who were living in two geographically defined areas in or close to the towns of Kuopio and Joensuu in eastern Finland

Results

Of the 1409 participants of the CAIDE study, 875 (62%) were women and 534 (38%) were men. They were aged from 39 years to 64 years at the midlife examination with a mean age of 50·4 (SD 6·0) years, and from 65 years to 80 years at the late-life examination with a mean age of 71·3 (4·0) years. Mean follow-up was 20·9 years (4·9). 4% of participants were diagnosed with dementia. Participants with dementia were older, less educated, and more commonly had vascular risk factors present at midlife

Discussion

Several modifiable and non-modifiable risk factors for dementia are known today. Our study shows that the dementia risk score created with the risk factors present at midlife predicts the future risk of dementia well. However, the dementia risk score needs to be further validated in another population. Eventually more variables could be added to the dementia risk score to improve its predictivity.

The AUCs for both the models used in our analyses were similar. The AUC values were between 0·70

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