In her 2024 Wellness Academy lecture, Rachel Whitmer, PhD, a leader in public health sciences and neurology, offered critical insights into protecting our brain health as we age.
In a thought-provoking Q&A, she addresses the impact of genetic factors like ApoE4, the role of lifestyle changes in mitigating cognitive decline, and emerging research on dementia risk and resilience. This session provides a comprehensive look at actionable steps individuals can take to support lifelong cognitive health, even when genetic predispositions may elevate risk.
About the expert: Rachel Whitmer, PhD
Rachel Whitmer is a tenured Professor of Public Health Sciences and Neurology, Chief of the Division of Epidemiology at the University of California Davis (UC Davis) School of Medicine and Co-Director of the UC Davis Alzheimer’s Disease Research Center. Professor Whitmer was the first female ‘Target of Excellence’ hire at UC Davis School of Medicine, a special hiring mechanism to recruit high impact scientists who are internationally renown experts in their fields and will bridge needed gaps in the research mission of the university.
Q&A with Rachel Whitmer, PhD
This transcript has been edited for clarity.
Q: We had a number of questions come in, and one of the topics overlaps with genetic predispositions. How should we think about our ApoE status? Many of us have learned from genetic testing that we’re ApoE4 carriers. How should we approach this information?
Dr. Whitmer: Yeah. Thank you for that question. So having ApoE (E4) is not necessarily a rare thing. It kind of ranges in the population from 20 to 30%. It does elevate risk, but the positive side is that there’s been research looking at risk factors and lifestyle changes. And people who are carrying E4 seem to benefit even more from making life’s lifestyle changes.
I think it’s also very important to understand that having E4 does not mean at all 100% that you are going to get Alzheimer’s disease or a related dementia.
It elevates your risk, but it does not mean that you are for sure going to get it. So it’s I think about it as part of the information. And when I think about my own brain health and what I should be doing to maintain my brain health, understanding that gives me information to feel empowered to make life lifestyle choices.
And I think it’s great to know that people who are E4 seem to benefit even more from these lifestyle changes.
Q: Are there any other genetic predispositions that are being looked at in terms of, influence, seeing our, urgency toward making some of these lifestyle interventions to have the maximum impact?
Dr. Whitmer: Yeah, there’s a lot of work being done right now trying to understand how groups of genes work together. We haven’t be able to find a genotype, such as E4, but there are things called propensity risk scores, where people are looking at clusters of genes.
This is relatively new work, and I think we are going to see some exciting findings coming out in the next few years to understand how people who have a higher genetic risk score, which means, having a number of snips that very slightly elevate risk, but perhaps having some of them or combinations of them and how that plays out when we understand risk and resilience over time. I think we will see some new findings in the next five years on that.
Q: For someone in their early 80’s, who can’t change their early life choices, what can they do now from a protective mechanism to prevent further decline?
Dr. Whitmer: Yeah. I am very passionate about this topic. We do have a study where everyone is in their 90s. And it’s true, you know, you can’t time travel. So what do you do today? What comes to light is that at any age, it’s important to stay active both physically and mentally.
There are a lot of studies out there looking at social interaction, social engagement, and physical activity as it relates to cognitive health. There are also wonderful studies that have looked at how people spend their time, such as spending it outdoors. Additionally, there was a study that compared people who exercised outside vs indoors. So taking a walk outside versus in an indoor or track; people being outside, it seemed to particularly affect their brain health and their happiness.
So the things we want to avoid are being sedentary, being inactive. And you want to avoid social isolation. And this becomes more important later in life. So I think staying engaged, interacting, being outside, being active, and even volunteering.
We’ve done some work looking at volunteerism and found that some people who volunteer, have better cognitive function. And we’ve also looked at people who continue education later in life. And it doesn’t necessarily mean going back to college per se. But participating in seminars, courses, certificates, online workshops, those all seem to benefit brain health as well.
Q: What about risk factors in terms of what you mentioned and the lifestyle interventions? How would you comment on the risk factors with people who are under going treatment with medication?
Dr. Whitmer: Yeah, that’s a very important point because we know what’s good for the heart is good for the brain, and cardio-metabolic risk factors, particularly over the lifetime, do play a role in your brain health later in life.
But absolutely, if you are being treated than one, you’re doing everything that you can. And two, it absolutely benefits your brain. So one perfect example is that if you have type two diabetes, which is becoming more common, it is really important to make sure that your glycemic control is appropriate, which of course is something that your doctor would be working with you on anyway.
So this is a great outcome, through trying to avoid complications of diabetes through appropriate blood sugar and glycemic control, you’re also benefiting your brain, especially your brain over the long term. We have done some work looking at blood sugar control and glycemic control over one or more decades and we saw that people that had appropriate control over their life time were at much lower risk of developing dementia.
So treating these risk factors is absolutely good for your brain.
Q: Next, there’s a question about lipoprotein A. Can you discuss this and any associated risks?
Dr. Whitmer: Something I have been thinking about a lot because there is some family history. There are some genes that seem to make some people’s lipoprotein levels very high and there is not a typical treatment in how to lower lipoprotein A. But what I think is very important, is that if you do have high lipoprotein A, its more important to think about controlling your, what we call your ‘bad cholesterol’ or your low density lipids.
This was something new that came out in the Lancet report, was that they weren’t talking so much about high cholesterol in general, but that low density lipid, seems to have emerged as playing more of a role as being a modifiable risk factor.
So if you have high lipoprotein A, you have more of a reason to look at and try to control the rest of your cardiovascular risk factors. There are some studies currently underway, with no results yet, that are looking at this questions, researching how lipoprotein A and how it is associated with cognitive changes.
Q: In terms of impact of behavioral interventions patients might be taking for recreation, such as marijuana or the use of psychedelics. Any comment on how those impact brain health specifically?
Dr. Whitmer: I think that is a really relevant and timely question. There’s been a large increase in both of those things at a population level, particularly in our younger population. We really do need to understand how it affects brain health and brain health over the long term. I don’t know currently of any clinical trials that are examining this so the bulk of the evidence on the exposure to marijuana are based on retrospective studies where we are interviewing people that are older, measuring their cognitive function, and asking them about their prior use.
There was a study that came out of the Cardia Study, a large study following people’s cardiovascular risk factors that’s being done at five sites, California being one of them. It is a long term observational study. There was one study that came out that showed a modest association between people in their 50s who reported prior, when they were in their 20s or 30s that they had a high use of marijuana, and their cognitive function was slightly worse than their counterparts who had not reported that. So that’s observational data, it’s not a clinical trial.
But I think the question is out there, what does this mean today? We know that the marijuana products today are very, very different from the marijuana products of yesterday and have much higher concentrations of THC. And we know that in the short term, it absolutely can affect processing speed and mental health. What does this mean over the long term? What are the young people of today going to look like in 40, 50, 60 years when they are older later in life? And we don’t have that answer yet.
So, I think we need to focus on the short term studies, which seem to suggests, probably not something good for brain health.
View Dr. Whitmer’s full Wellness Academy Session to learn more about protecting your brain as you age.
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