LONDON – Twelve modifiable risk factors appear to account for more than half of the variation in dementia risk associated with socioeconomic status.
When integrated into an 18-point risk score, dubbed the “Lifestyle for Brain Health” (LIBRA) index, they accurately predicted dementia risk in more than 6,300 subjects who were followed for 7 years: Dementia risk increased by 30% for every 1-point increase on the LIBRA score, Sebastian Koehler, PhD, said at the Alzheimer’s Association International Conference.
Dr. Sebastian Koehler
According to Public Health England, 52% of citizens choose dementia prevention as a top health priority, but almost the same number believe that “there is nothing anyone can do to reduce their risk of getting dementia.” The LIBRA score could be employed as a public health measure to counteract that misunderstanding, he said.
“We can reduce the gap in risk that’s related to low socioeconomic status by improving health in that group. But we know that public health measures and messages are taken up much better by those with higher socioeconomic status. We think the first step is to raise awareness among this group that there is something we can do about dementia risk. And then we can reach out to this vulnerable group and design measures and messages that speak to both their needs and their resources.”
The 12 risk and protective factors were originally identified by epidemiologist Kay Deckers of Maastricht University, who drew them from a large meta-analysis published in 2015 (Int J Geriatr Psychiatry. 2015 Mar;30[3]:234-46).
They are the following:
• Diabetes.
• Hypertension.
• High cholesterol.
• Smoking.
• Obesity.
• Physical inactivity.
• Depression.
• Coronary heart disease.
• Kidney disease.
• Diet.
• Alcohol.
• Mental activity.
Dr. Koehler and his colleagues used them to create the weighted LIBRA score, which computes an 18-point risk level ranging from –5.9 (lower risk) to 12.7 (higher risk). Among the factors that reduce dementia risk are high cognitive activity, healthy diet or Mediterranean diet, and low-moderate alcohol intake. The others all increased risk. Each of the factors was assigned a point value based on its percentage of risk reduction or increase. For example, high cognitive activity reduced risk by more than 3 points, but depression increased it by 2 points. The investigators then validated this score on 6,346 participants in the English Longitudinal Study of Ageing, who were followed for up to 7 years.
Dr. Koehler’s study, however, was not just a LIBRA validation study. He wanted to correlate these protective and endangering factors with each subject’s socioeconomic status, and determine how much of the risk difference generally accredited to wealth was related to the LIBRA factors.
After 7 years, about 9% of the study sample developed incident dementia. These subjects were significantly older than those who didn’t (77 vs. 64 years). They were more likely to have lower education attainment (58% vs. 37%), and more likely to be poor (44% vs. 29%).
On the LIBRA risk factors, the participants who developed dementia were significantly more likely to have heart disease, diabetes, hypercholesterolemia, hypertension, and depression, although not significantly more likely to be obese or to smoke.
On the LIBRA protective factors, they were significantly less likely to be low-moderate alcohol users (37% vs. 57%), to have high cognitive activity (17% vs. 45%), and significantly more likely to be physically inactive (59% vs. 24%).
Two survival curves compared the incidence of dementia related to wealth and LIBRA score. Subjects of low socioeconomic status experienced an increase in dementia risk very similar to those with high LIBRA scores. Dr. Koehler also conducted three analyses that examined the effects of wealth on dementia risk: the total effect of wealth, the direct effect of wealth, and what he called the “indirect wealth effect.” This examined the impact of wealth on LIBRA scores, followed by the effect of these scores on dementia risk.
This final model concluded that 56% of the risk imposed by low socioeconomic status was actually attributable to LIBRA scores. In other words, low socioeconomic status was directly tied to both increases in physical and mental risk factors, and decreases in physical and mental protective factors.
“Health inequalities influencing dementia risk exist because of socioeconomic differences between people,” Dr. Koehler said. “People with less wealth have a higher frequency of being exposed to risk factors for dementia that are potentially treatable.”
The LIBRA study is part of a larger dementia prevention study called Innovative, Midlife Intervention for Dementia Deterrence (In-MINDD). Dr. Koehler had no financial disclosures.
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