Norman Swan: Some experts argue that about 50% of dementia is preventable through things like maximising education early in life, keeping your blood pressure down, not smoking, having a good diet, avoiding diabetes and obesity, reasonably intense exercise, maintaining a good social network, and maybe even now Metformin.
Well, a consortium of Australian universities and research centres has just published the results of a randomised trial. This is a randomised trial, not an observational study, into a cocktail of nondrug interventions to see if they help people whose thinking and memory are impaired or declining. Professor Kaarin Anstey is director of the University of New South Wales Ageing Futures Institute and is a senior research scientist at NeuRA. Welcome to the Health Report, Kaarin.
Kaarin Anstey: Hello.
Norman Swan: So tell us about the people you studied in this randomised trial.
Kaarin Anstey: So this trial focused on people who have either subjective cognitive decline or mild cognitive impairment. So subjective cognitive decline is when you feel that your cognition is deteriorating or someone who knows you well thinks that it is but we can't actually identify a change on clinical testing. But it has been shown that that group are actually at increased risk of developing mild cognitive impairment and dementia. So we targeted that group, and then people who also had a cognitive impairment that was clinically assessable.
Norman Swan: So I'm feeling more forgetful, but when I go to a neuropsychologist they don't find anything abnormal.
Kaarin Anstey: Yes.
Norman Swan: And what were the interventions you studied?
Kaarin Anstey: Right, so there was a control condition which was an online educational program that we've developed and assessed in healthy middle-aged adults who are at risk of dementia, and that is an educational module that tells you about dementia and risk factors, we have an educational module about physical activity, one about diet and one about cognitive engagement. And then the intervention group received the same modules but they also had a face-to-face session with an exercise physiologist and two follow-up appointments, and a face-to-face session with a dietician who gave them very tailored dietary advice and followed them up as well. And they were also given a subscription to a brain training package.
Norman Swan: So let's talk about the diet. You were encouraging them to get onto the Mediterranean diet, is that right?
Kaarin Anstey: Yes, that's correct. These systematic reviews have shown that the Mediterranean diet is associated with about a 30% reduced risk of Alzheimer's disease. So that was the diet that was selected for this intervention.
Norman Swan: And the exercise? Did it matter what kind of exercise they were taking? Because I understand it's got to be reasonably intensive to work.
Kaarin Anstey: Well, for this trial what we've done, we've now conducted a few of these Body, Brain, Life trials, and we've got to the point now where we leave the exercise prescription to the exercise physiologist to that it can be tailored to the individual. So we know from systematic review literature that meeting national guidelines is associated with a 30% reduced risk of dementia, which is 150 minutes a week, you know, the usual guidelines that we hear about. But we also know it's very, very difficult to change habit and to get people who are inactive to start exercising. So for this trial we left it to the exercise physiologist to design a personalised program, which we thought was more appropriate and we think that's the way to go in the future.
Norman Swan: And did they stick with the brain training, because people often don't. It's a nice idea but
Kaarin Anstey: That's a really good question. No. So our trial, like also the FINGER trial which is the other very famous multi-domain trial, had poor adherence to brain training. So what we find isand we've seen this in other studies as well, people start off very enthusiastic but they get bored with it. So we had about a 20% adherence to the full program of brain training. Most people started the brain training but they didn't stick with it.
Norman Swan: And what were the results?
Kaarin Anstey: So this trial showed that the people who received the more intensive intervention, they had cognitive improvement at a six-month follow-up.
Norman Swan: So an improvement, rather than just the decline stopping, they actually got better?
Kaarin Anstey: So what we see with cognition is that when we repeat tests, people do better from practice effects. So we tend to see a slight improvement over a period of six months, and in normal ageingwell, with people with cognitive impairment we'd be seeing a decline.
Norman Swan: It seems like a very short time to get an improvement.
Kaarin Anstey: Yes, it was a short time but this is an at-risk group where we are seeingthe reason this particular trial was targeting this group is that we do see conversion from these conditions into dementia. So people with mild cognitive impairment have a 5% to 10% chance of progressing to dementia within 12 months. People with subjective cognitive decline have twice the risk of developing mild cognitive impairment. So this is a group who are at risk of transitioning fairly quickly, which is why they are a key group for intervention.
Norman Swan: Often randomised trials are into single things, like brain training or the diet or the exercise. How valid is the package of stuff? I realise it's more real-world but it also creates its own problems in terms of knowing what works.
Kaarin Anstey: That's a very good question about this whole multi-domain approach. So what has happened in the field of dementia risk reduction is that people did focus on individual risk factors like physical activity, diet et cetera, and we are at the point now where we do have evidence, we've got the WHO guidelines based on the intervention evidence for each of these individual risk factors, but the consensus has been that we really need to target more than one risk factor at a time because we don't know exactly which risk factor is salient for which person, and we think we will get a much bigger effect if we target everything at once. That does mean we can't then go back and unpack and work out for which person which risk factor was important.
Norman Swan: Once you've cracked the egg, you've cracked it. And just very briefly because we are running out of time, Kaarin, you were using the ANU's dementia risk score. Just very briefly, what's this dementia risk score.
Kaarin Anstey: So that's a risk score that I led the development of that was based on data synthesis. So we synthesised all of the literature on risk factors for dementia that was available at the time, and we developed a weighted composite risk score which is freely available and people can go in and assess their risk, and then that was validated against three international cohort studies, including the US Cardiovascular Health Study, the Rush Memory and Ageing Study, and the Swedish Kungsholmen Project, and it was shown to predict dementia in those cohorts, and we've also validated it in an Australian cohort. So we use that as what we call a surrogate outcome measure, particularly in adults or in trials where we are not going to follow-up people long enough to see if they develop dementia.
Norman Swan: Well, we will have a link to the dementia risk score on the Health Report's website. Kaarin, thanks for joining us, that's fascinating work.
Kaarin Anstey: It's a pleasure, thank you.
Norman Swan: Professor Kaarin Anstey is director of the University of New South Wales Ageing Futures Institute and is a senior research scientist at NeuRA.
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Diet, exercise and brain training the cocktail that could help prevent dementia - ABC News
