How can we better understand the risk factors for dementia?

Did you know, Australia is looking at doubling our current figures to a projected 1 million people with dementia by 2056? While our lifestyles have been shown to impact the chances of getting dementia, there is no national prevention plan because we don’t yet know enough about the disease to fully advise. Our guests for this episode, Professor Henry Brodaty and Dr Martin McNamara are conducting separate studies to increase our understanding of dementia and its prevention in the Australian community.

Gretchen Miller: Hello and welcome to another episode of PreventionWorks from The Australian Prevention Partnership Centre. I’m Gretchen Miller. Did you know, Australia is looking at doubling our current figures to a projected 1 million people with dementia by 2056? While our lifestyles have been shown to impact the chances of getting dementia, there is no national prevention plan because we don’t yet know enough about the disease to fully advise.

Our guests today are involved with sorting that out. Each of them is running separate studies that will increase our understanding of dementia and its prevention. Henry Brodaty is Scientia Professor of Ageing and Mental Health, at UNSW Sydney, and he’s Co-director of the Centre for Healthy Brain Ageing, also at UNSW. This is where he leads the Maintain Your Brain trial, which is a randomized control trial of multiple online interventions designed to target modifiable risk factors for Alzheimer’s disease and dementia. Professor Brodaty also happens to be a part of the team here at the Prevention Centre, advising on our own project, which is looking at the proportion of dementia in the community that is preventable.

And on that research, we also have Dr Martin McNamara, Deputy CEO of the Sax Institute, the Prevention Centre’s host organisation, and he leads complex programs that bridge the gap between research and practice, including the 45 and Up longitudinal study that is so critical to both these research investigations. So, I began by asking Henry about this remarkable statistic. There’s evidence that lifestyle changes can reduce the risk of dementia by 40%, or even more. So, let’s set the scene, what does that statistic mean?

Henry Brodaty: It means that there are things that we can do in our life now to lessen our chance of developing dementia or to delay its onset. What we know is from population studies and we know that there are associations between certain lifestyle or environmental factors and the chance of developing dementia. If we were able to reduce those factors by say 25%, there would be three or four million fewer people in the world with dementia right now. For example, if we had better childhood education, if we had less midlife obesity, less midlife hypertension, if people didn’t smoke, if people kept cognitively active during their lives, ate healthily, treated high blood pressure, wore hearing aids if they were deaf, socialized more, avoided air pollution or head injuries, then they would have less risk of developing dementia.

Gretchen: How conclusive is the evidence?

Henry: You can’t do a randomized control trial. You can’t tell people to eat a certain diet for 30 years and another set of people not to eat that diet, or you can’t tell people to get head injuries and not have head injuries, so you can’t do the gold standard which is a randomized control trial. These are all epidemiological studies and they are associations but when the associations are consistent across multiple studies and there are now three sets of analyses: one from the US; one from the UK; and a second one from the UK, all coming up with the same answers, and extending it, so we thought it was 30%, then 33%, and the latest Lancet Commission now says 40%, and they have added more factors. So, the 2017 Lancet Commission added hearing loss which we weren’t really aware of, but there are three good studies with long follow-ups, up to 17 years, showing an association. The good news is that people who wear hearing aids ameliorate that loss. And they’ve also added new risk factors and the new one is air pollution which is interesting that the percentage it contributes may only be one or 2% but it’s important and we need to start addressing it.

Gretchen: Is it isolation that deafness causes that can influence things?

Henry: One of the theories is that people who socialized less, have less social context and don’t have someone to confide in, have a higher rate of dementia, that’s one of the empirical facts shown and that maybe hearing loss acts through that mechanism, but there are different sorts of hearing loss, and you’d imagine that all sorts of hearing loss should cause if that’s the mechanism, so I’m not convinced that’s how it’s happening.

Gretchn: I’m possibly just still young enough to be able to influence my chances of getting dementia or not getting it, what might I personally be doing to reduce the risk?

Henry [5:07]: Well, let me preface my comments by saying, you are never too old to do these things and you are never too young to do these things. There may well be critical periods and of course we form our brain more as we are younger, so that may have the greatest impact. But there is evidence that education at any age is beneficial so people if they’ve left school at 14, and I have friends who for various reasons were unable to complete school, but have self-educated over the years, are very bright and very active cognitively, so that may also be protective. The other thing is socialization and people who have more social context, who volunteer, who have people they can confide in, who have more quality social context, are less likely to develop dementia. And the converse, is people who have less are more likely, and loneliness, independent of sexual context, may be a risk factor too. Physical activity is the most important thing, you should be exercising at least five days a week and should be doing at least half an hour a day. Many people say an hour a day, and it should be getting hot and sweaty, it shouldn’t be comfortable, should not just be comfortable strolling with your friend around the shopping centre, that’s not exercise. There is also evidence that you need to mix up your exercises so not just aerobic but also doing some weights or pulleys, resistance training as well.

Gretchen: So that’s the physical aspect of it, what else can I do?

Henry: You can be eating well, there’s increasing evidence that a Mediterranean type diet, which is rich in plant-based foods, has a base of grains and vegetables, fruits, lesser amounts of poultry, cheese, fish, and even smaller amounts of red meat and sweets. So less than a third of our intake should be fat and less than 8% should be saturated fat, so polyunsaturated is much better for us. We will never be able to prevent dementia completely, what we’re trying to do is reduce the risk or delay the onset, ideally, until after we die, so just reducing the risk by 50%.

Gretchen: So the thing is, it’s not about me, and every individual is it? Why is it not about me, why is it about the population level of engagement?

Henry: Just delaying the onset by five years would reduce the rate of dementia, the prevalence, by 50% across the population. If we can get people to eat less salt, there will be less hypertension, without worrying about individuals how much salt they want, we want people across the population to be eating less salt. It’s looking at the packaging of fast foods in the supermarket, it’s looking at what restaurants do, it’s attacking it at a population level, that’s what we need to do, as regards dementia prevention.

Gretchen: And that’s why we need a policy because we can all make our own individual efforts but what we’re looking at is reducing it in the population overall. And that’s where policy comes into play right? So, as you say, reducing the amount of salt-enriched foods in supermarkets affects us as individuals but it also affects the population.

Henry: That’s very good, yes.

Gretchen: The Australian Prevention Partnership Centre is currently reviewing the literature to quantify the relative contribution of risk factors, but it’s also drawing on another significant study to refine what we know about dementia in Australia. It’s called 45 and Up, so I asked Martin McNamara, what does this study offer?

Martin McNamara: So, the 45 and Up Study is the largest cohort study in Australia, and it compares really favorably to other large cohort studies all around the world in terms of its size and breadth. It was established back in 2006 and at that time we recruited over 260,000 people in New South Wales over the age of 45. Importantly, when we recruited people to the study, we got their consent to follow them up over the years and continue to ask them various questions about their lifestyle, their health behaviors, and the sorts of things that were a part of their lives. We also got their consent to link data about the health services use, their visits to general practitioners and hospitals, and their use of pharmaceuticals to that information we collect around their healthy lifestyles and behaviors. And that means over time we have built a really important asset for understanding the health of the population but crucially understanding how the health of the population changes over time and how it changes in response to lifestyle and different behaviors of people within 45 and Up.

Gretchen: I’m wondering how you’re using it then for this research into dementia, what are you linking up with?

Martin: Importantly, with a study like 45 and Up people commenced in the study back in 2006 so it means we’ve got over 15 years of data on participants, so 15 years of information on people’s health and their health-related behaviors, people’s lifestyles, their use of hospitals, the use of general practitioner services so we know a lot about how their health and lifestyle has changed over the years. And we also know a lot about people that have recently been diagnosed with dementia or other sorts of cognitive decline and that means we can track back and understand some of the factors that may have led to dementia and other cognitive declines, and understand where if we had of been able to intervene earlier in people’s lives we might have been able to prevent some of those outcomes.

Gretchen: What are some of the variables that you’re looking at, that you understand will affect dementia and that 45 and Up will be able to help you with? And I think what’s particularly interesting about it of course is it’s a very helpful study because of the age of the cohort, right?

Martin: That’s right. It means we had people that were 45 at that time, but also people in lots of different age categories, including right up to over 85 years of age. So, what we will do with this study is look at the various risk factors that are currently understood for dementia, that includes things like overweight and obesity, physical inactivity, alcohol consumption. Things like people’s socioeconomic status, whether they have co-morbidities like hypertension or diabetes, and try and understand whether different combinations of those sort of risk factors are leading to dementia outcomes, and also try and understand which actions on which of these risk factors would result in the best outcomes for dementia.

Gretchen: You’re actually combining 45 and Up with a literature review as well, and you’ll look at predictive modeling that uses data driven methods, guided by that literature review?

Martin [11:48]: That’s right, so we are certainly informed by the literature that has already been produced on dementia and its risk factors. Importantly with 45 and Up we can examine the risk factors identified in the literature and how they’re playing out in the 45 and Up population and extrapolate that to the Australian population. And we can also examine additional risk factors because of the longitudinal nature of 45 and Up and the ability to track people’s health and wellbeing over time. I think what’s really important here is, the more we can understand the influence of different risk factors on dementia, the better we can target prevention efforts to combat those risk factors and reduce dementia in our population.

Gretchen: I asked Professor Henry Brodaty whether the risk factors for dementia were widely understood by the public, or by general practitioners (GPs), or policymakers. And he said, while we know all about the risks of, say, heart disease and GPs are now well accustomed to integrating attention to blood pressure and cholesterol into their practice, dementia is another story. Neither GPs nor the public are particularly focused on its prevention.

Henry: Even though if we do surveys of older people what they fear most in the world is not climate warming, is not the economy, it is not even COVID – it’s dementia. People are terrified of dementia. There are two movies that are current at the moment, there’s The Father with Anthony Hopkins, he received an Academy Award for that, and Supernova with Colin Firth and Stanley Tucci, fantastic movies and really describe what it’s like to be a person with dementia.

Gretchen: So, this socio-cultural indication is that we are terrified of dementia, but we don’t know all the things that we can do and in fact, neither really do our GPs, what about our policymakers?

Henry: So, our GPs are knowing it but I don’t think they are pushing it yet. We have been involved in some studies, my colleagues at the Ageing Futures Institute at UNSW, with GPs to try and improve their capacity as preventative agents. Policymakers, I don’t think are very much attuned to this, this may not be localized to dementia, that we’re much more invested in treating disease rather than preventing disease.

Gretchen: So why then don’t we already have a nationwide policy on dementia prevention, and how badly do we need one?

Henry: I think we haven’t had one because the evidence hasn’t been strong enough, but the evidence is now accumulating and we just have to work out ways to deliver it. It’s very hard to get people to change their habits, to start exercising, to start eating healthily, just look at all the number of diets and gurus around about what you should eat. And people go on these fads but don’t maintain them, which we’re trying to rectify by doing an online intervention called Maintain Your Brain. [14:43] So, we need to find a way to deliver it and convince people that this is good for them. And it’s hard to convince people to do something for 30 or 40 years, you know in your midlife, that’s going to save you having dementia at the age of 80.

Gretchen [ 15:03] We specialize in cognitive dissonance.

Henry: Exactly.

Gretchen: So, we don’t have a policy because we haven’t had the evidence, but the evidence is coming up and actually here’s another fact that’s pertinent to my cohort, Australian women are more likely to die of dementia than heart disease now and it’s our main cause overall of disability. So, what’s needed to bring about such a policy? What might a policy look like?

Henry: Well, the policy needs to be at various levels. At the ground up, that is people wanting to do these things and having some media campaigns to convince them this is something they should be doing. I guess the middle level is that the healthcare practitioners like GPs should be pushing this and really encouraging people and from the top down facilitating this. So, whether it’s having spaces for people to exercise, environmental things certainly around pollution I mentioned earlier, but having green spaces and making it easy for people to exercise. If we had a program that people could do for free perhaps, I mentioned the online one that we are developing, Maintain Your Brain, and if we can show that works that would be something they could do. We can’t make people do these things we can only lead them to it.

Gretchen: So how does the Prevention Centre study refine what we already know about dementia, with policymaking in mind?

Martin McNamara: A key part of the design of this project is working closely with policy agencies and other stakeholders that have got a hand on the lever of how we might change our efforts to combat dementia. I think that’s a really important attribute of this work so we’ll certainly be doing the data analytic side of this which is understanding the different impact of risk factors for dementia and understanding what portion of those might be prevented. But importantly, along the way we will continue to engage with policymakers and government and other stakeholders that are interested in dementia to try and tease out what are the most feasible sets of actions to take that might actually drive down dementia in our population.

Gretchen: Henry Brodaty and the Centre for Healthy Brain Ageing have, as we mentioned earlier, their own research project, Maintain Your Brain, which will soon be doing its final follow ups. So, how did it work?

Henry: We had a grant from the NHMRC to do this study, and we recruited through the 45 and Up cohort, people aged 55 to 77, and we sent invitations to almost 100,000 people. Over 12,000 or 14,000 responded, there were certain eligibility criteria, people needed to have at least two risk factors for dementia and needed to do a lot of testing online so there was a demand on them. We ended up with 6236 and they were randomized into two groups, and they received interventions based on their risk factors. So, they could be physically inactive or have problems with gait, or with balance or falls, they could be not eating a healthy diet, or be obese, or have type two diabetes, or heart disease, so there’s a nutrition module. They could be cognitively not very active, so there was a brain training module, or they could have depression or anxiety, or had history of that and that was the stress reduction or peace of mind module, so there were four modules, and they receive one module every 10 weeks in the first year, so it’s an information group.

The second group got coaching in their modules, so the people, for example, doing physical activity would, if they had balance problems, they would be getting a lot of balance exercises, they might be getting aerobic exercise and strength exercises, depending why they needed to be in that, they also had videos. This was led by Marie Fiatarone Singh from Sydney University, who also led the nutrition module and we found over 90% of the population aged 55 to 77 were not being physically active by not eating well. That’s a lot. They had to fill in questionnaires about what they were eating each week, which was quite a load for them. The brain training was a series of 30 exercises doing three a week for 10 weeks and there are many companies now doing brain training online. This was led by Professor Michael Valenzuela now at New South Wales University. And again, they could get a graph to show how they were progressing over time, and then the peace of mind group, they used a module developed at St Vincent’s Hospital by Professor Gavin Andrews, which has been out there for a number of years and shown to be very successful. After they finished their modules, they then had booster sessions once a month and so that’s continued in years two and years three, for most of the people they have finished the intervention and have started the follow ups. By October, analyzing our data, we should have results and if you do this interview again, this time next year, I could tell you what they are.

Gretchen: So, you’re measuring risk factors and cognition and you’ve told me what the training looks like, what are you hoping to do with it?

Henry: Well, if we can show this is beneficial and if we can show that there are people with a more active intervention that have less cognitive decline, then this is a powerful argument to say let’s start rolling this out. It’s eminently scalable nationally and internationally and it’s the biggest study of its kind in the world and we are hopeful. We haven’t looked at the data we are not allowed to until the trial is finished and then we will be looking at what are the differences between people who do the intervention, people who are the nerds or conscientious, what are the characteristics of people who will do this? Is it people who’ve got a family history and are terrified of dementia? So, there may be a lot of drivers, it might be personality, it might be exposure to knowing what dementia is like that really drives them.

Gretchen [20:50]: Once you do this final follow up, what will you hope to do with the results?

Henry: Well, first of all, we’d like to get some more money to continue the follow-up because three years is not going to be enough to show a decline in dementia rates, it can show a difference in cognition but not in dementia rates. So, we probably need a 10-year follow-up but if we can show positive results, to your question about how do we influence policymakers, we can say look, here’s a product, here’s the platform, here are the modules, now go for it. That’s what we would like to see happen.  

Gretchen: To draw us a close, I asked Martin McNamara, whether his team were expecting any surprises while undertaking their research.

Martin: I guess with any complex condition like dementia you’d expect that a range of risk factors are playing into dementia outcomes in our population, so you’d expect that there’s a combination of factors that are driving dementia. I think what we will be interested in learning more about is whether there are particular combinations of risk factors that we might better target that will have the biggest impact on reducing dementia outcomes in our population. If we can find a small number of risk factors or a combination of risk factors that if we combine our prevention efforts and target those risk factors will have a real impact on dementia outcomes, that would be a pleasing finding and perhaps a really positive outcome of this work.

Gretchen: I wonder what this research means to policymakers? What could this information, given in this way, do to develop policy across the state and across the country?

Martin: Well, the real benefit of a project like this is enabling the policy community to better target their efforts to reduce dementia in our population. So, clearly, there’s a range of risk factors that have already been identified for dementia, we’ll be looking at those, we’ll be looking at other potential risk factors as well. But what will be important from a policy perspective is to narrow down where best to target their efforts to prevent dementia in the population. If we can identify some best buys, some risk factors, or some combinations of risk factors that if they were reduced that would have a big impact on dementia in our population – that would be the best outcome possible for this work.

Gretchen: We know that education campaigns work when it comes to lifestyle-related chronic disease, we’ve seen that happen with skin cancer and we’ve seen it happen with smoking. So having an education campaign is one thing but having a successful one is another especially with something which is so off in the distant future of our lives. What kinds of education campaigns can help?

Martin: Clearly education is a really important component, but education alone will have only a modest effect on dementia outcomes in our population. For prevention efforts to be successful, they really need to work at multiple levels, so it requires mobilizing action across a range of different parts of government, across the NGO sector, and also action that speaks to our socioeconomic status in our population.

Gretchen: It is the obvious thing, isn’t it? It’s having public transport, it’s being able to walk, it’s being able to cycle or go to a park, it’s having libraries where you can use your brain.

Martin: Absolutely, having access to high quality, healthy foods and having the right set of circumstances to encourage physical exercise or health and wellbeing generally – all those things will have an influence on dementia outcomes, and we will be looking at, and understanding, where the efforts to have the best effect on dementia outcomes can be made in our population.

Gretchen: Dr Martin McNamara, he’s Deputy CEO of the Sax Institute, and with him, Professor Henry Brodaty from the Centre for Healthy Brain Ageing at UNSW and you will find more information about both these studies on The Australian Prevention Partnership Centre’s website. I’m Gretchen Miller, thanks for your company and see you next time.

Show notes