SALZBURG, AUSTRIA — A risk score that predicts the likelihood of a middle-aged person developing dementia within 20 years has been independently validated in an ethnically diverse population, according to data presented at an international conference on Alzheimer's and Parkinson's diseases.
The Cardiovascular Risk Factors, Aging and Dementia (CAIDE) risk score originally was created using data from the CAIDE study, a population-based study of 1,409 individuals in a Finnish population in the 1970s (mean age 50.4 years). When the Finnish subjects were reexamined in 1998, 61 of the subjects were diagnosed with dementia.
Study participants with dementia were found to be older at the midlife examination (mean age 53.4 years vs. mean 50.2 years), less well educated (6.7 years of formal education vs. 8.7 years), and had more vascular risk factors—such as high blood pressure, high total cholesterol, and high body mass index, as well as a history of smoking—present at midlife than did participants without dementia.
Dr. Miia Kivipelto of the Aging Research Center at the Karolinska Institute, Stockholm, used the data from the CAIDE study to create a score that could predict the risk of developing dementia in later life.
The CAIDE dementia score uses age, years of formal education, sex, systolic blood pressure, body mass index, total cholesterol, and physical activity to determine an individual's likelihood of developing dementia within 20 years. (See table.) The risk of dementia was found to be 1% for patients with a score of 0–5; 1.9% for patients with a score of 6–7; 4.2% for those with a score of 8–9; 7.4% for a score of 10–11; and 16.4% for patients with a score of 12–15 (Lancet Neurol. 2006;5:735–41).
“When the cutoff was set at 9 points or more, the sensitivity was 0.77, the specificity was 0.63, and the negative predictive value was 0.98,” said Dr. Kivipelto at the conference.
Rachel Whitmer, Ph.D., an epidemiologist working at the Kaiser Permanente Division of Research, Oakland, Calif., validated the CAIDE dementia risk score in a sample of 9,480 long-term members of Kaiser Permanente's integrated health care delivery system, of whom 1,011 developed Alzheimer's disease or vascular dementia.
The study sample was ethnically diverse (474 Asian, 1,401 black, and 7,605 white) and included people from a wide demographic range.
According to Dr. Whitmer, she obtained results similar to those of Dr. Kivipelto by using the CAIDE score on the Kaiser Permanente sample.
In addition, Dr. Whitmer added more variables to the dementia risk score, including obesity, smoking, pulmonary function, and depression, but found that these did not improve the score's predictive value.
However, the addition of diabetes as a variable improved the predictability of the score for Asian patients, but not for black or white study patients.
“It seems like we're really onto something here,” said Dr. Whitmer. “It replicated really well and is so predictive in such a different population.”
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