New Tool Predicts Long-term Dementia Risk

Caroline Cassels

August 02, 2006

August 2, 2006 — A team of researchers has developed a method for predicting dementia risk that could help identify those who might benefit from intensive lifestyle consultation and drug intervention.

Using the dementia risk-factor score, which was developed by investigators at the Aging Research Center at the Karolinska Institutet in Stockholm, Sweden, older age, low education levels, hypercholesterolemia, hypertension, and obesity significantly predict future dementia.

"Our study shows that the dementia risk-factor score, created with the risk factors present at midlife, predicts the future risk of dementia well," the researchers, led by first author Miia Kivipelto, MD, PhD, write. However, they note that the tool needs to be validated in another population.

Furthermore, they note, although the dementia risk-factor score provides a quantitative estimation of the probability of becoming demented, it cannot definitely state whether a person will develop dementia and therefore "should not be used to label individuals as being demented or nondemented in the future."

The findings are published online August 3 in The Lancet Neurology.

A Simple Prediction Tool

Data from the longitudinal population-based Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study were used to assess 1409 individuals in midlife and again 20 years later for signs 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," the authors write.

Of the 1409 participants, 875 were women and 534 were men. At the midlife examination, the average age was 50.4 years; at the late-life examination it was 71.3 years.

At baseline, CAIDE study participants were given a self-administered questionnaire on health behavior, health status, and medical history, which included specific questions about cardiovascular and cerebrovascular events.

In addition, all subjects had cholesterol levels, diastolic and systolic blood pressure, and body mass index measured. At follow-up an average of 20 years later, these measurements were repeated. In addition, apolipoprotein E genotypes were analyzed and cognitive status was assessed.

Study participants who scored 24 or lower on the Mini-Mental State Examination at the screening phase were referred for further testing, which included thorough neurologic, cardiovascular, and neuropsychologic evaluations.

Finally, at the differential-diagnostic phase, subjects were assessed by brain magnetic resonance imaging, blood tests, cerebrospinal fluid analysis, and electrocardiogram.

Higher Scores Equal Higher Risk

Of the total study group, 61 study participants (4%) were diagnosed with dementia — 48 of whom had Alzheimer's disease. The authors report that future dementia was significantly predicted by an age of 47 years or older, an education level of 10 years or fewer, and the presence of hypertension, hypercholesterolemia, and obesity.

Using the model they developed, the researchers found that the higher the dementia risk-factor score, the greater the probability of dementia. "The dementia risk[-factor] score predicted dementia well (area under curve, 0.77; 95% [confidence interval], 0.71 – 0.83)," they write.

Risk for Dementia by Categories of Dementia Risk-factor Score

Category of Dementia Risk-factor Score
Dementia Risk, %
0–5
1.0
6–7
1.9
8–9
4.2
10–11
4.0
12–15
16.4

Practical Application

Based on these results, the authors note that hypertension, hypercholesterolemia, low physical activity, and obesity offer intervention opportunities, although they also point out that it is not clear from current epidemiologic evidence whether modifying these risk factors affects dementia risk.

In addition, although controversial, there is some evidence from studies looking at the prevention of cardiovascular disease in which dementia or cognitive impairment have been included as a secondary outcome that suggests antihypertensive drugs reduce dementia risk.

In the meantime, the authors note, the dementia risk-factor score draws attention to "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."

Lancet Neurol. Published online August 3, 2006.

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