Professor Kaarin Anstey
If we’re talking about Alzheimer’s disease, there is a known genetic risk factor that has a known increased risk associated with it. So if you were tested for that, you could say that you have an increased risk. But, at the same time, we know many people live a full life with this genetic risk factor and don’t ever develop Alzheimer’s disease. So it’s not a sentence to find out that you have that risk. And, at the same time, there are people who don’t have that genotype, who do develop Alzheimer’s disease. So, even when we’re looking at genetics, it’s not possible to say to an individual, you will definitely develop Alzheimer’s disease. All we can do is talk about whether you have characteristics that increase your risk relative to the population, but we could never say for the individual, your personal risk is this, because there are so many other complicating factors.
So the example I like to use is smoking and lung cancer. We know that if you smoke you’ve got a greatly increased risk of lung cancer, and of dying of lung cancer. But there are people who develop lung cancer who never smoke, and there are smokers who never develop lung cancer. There are also people who have a genetic risk factor for lung cancer and that can increase their risk, or if they have that genetic risk factor and they smoke, they’ve got a greatly increased risk of developing lung cancer. And it’s pretty much the same with Alzheimer’s disease. The things that we know increase the risk of Alzheimer's disease, apart from your genetics, the biggest risk factor is age. There’s nothing we can do about age.
So, if you wanted to assess your risk, there are a few tools that are available to assess risk. You can do some self-report risk assessment. We've developed an online self-report risk assessment tool at the ANU, that can give you feedback on your risk profile for Alzheimer's disease, and tell you if you’ve got things you can modify to reduce your risk. And there are some clinical assessments that have been used in clinics, particularly in the United States where people have developed a clinical risk assessment for midlife adults, or that have developed in Finland where they can check things like high cholesterol, high blood pressure and so forth, and they give you a score. It’s not as advanced as the field of heart disease, so in heart disease you can go and you can get a Framingham Risk Score done which will tell you your risk of developing heart disease in the next 10 years. We’re not at that point in dementia research; we haven’t been able to pin it down to a time period. We do have risk assessment, but we need the research to develop to get us to that level, the specificity of diabetes and heart disease.
What we did at the ANU was we did those meta-analyses that I’ve already discussed and also looked at published meta-analyses in the literature, and we created a risk assessment algorithm based on the best available evidence at the time for all of the factors known to increase the risk of Alzheimer's disease. So we developed the algorithm and we have risk and protective factors in our scores, so some things actually reduce your risk, and then we developed a questionnaire that assesses each of those risk factors. And the questionnaire is comprised of subscales which are taken from the epidemiological studies that actually linked that exposure to dementia. So, for example, cognitive engagement has been linked to the risk of dementia in two studies, and we use the actual questionnaire that was used in those two studies in our scale.
And that’s another issue around measurement. So one study might find something, but if you use a different questionnaire you may not find the same result. So all the measures that we’ve used in our questionnaire have been linked to dementia. And then we’ve made that available online; it’s free to the public, anybody can assess their own risk and then we provide feedback on what you could do to modify that risk.
So it’s at a fairly general level, because this is a publically available website, it’s not a medical clinic, and it doesn’t involve any medical tests. So, for example, we don’t test your blood pressure, which you’d need to have done by your GP. If you’re really concerned, you can print out a PDF of your assessment that we’ve created, and you could take that to your GP. Otherwise, it gives you fairly general information about risk reduction, but you can get much more detailed information from other websites or from your local doctor.
So with our risk assessment tool, it focuses on understanding your risk, not telling you you’ve got this percentage or that percentage risk of developing Alzheimer's in so many years, and I think it’s important to know your risk profile so you know what you can modify. And then you can change it in time to prevent that risk factor impacting on your brain. People say to me quite often, oh, I just wish I could find out accurate information about what I can improve in my lifestyle to reduce my risk of dementia.
We don’t have a single blood test or medical test that will directly tell you your risk of developing Alzheimer's or another type of dementia. There’s a lot of research ongoing at the moment that’s trying to develop blood tests, and you might see things in the media about research results, but so far there’s nothing that’s been validated and rigorously tested and released onto the market.