The Impact of Social Isolation and Loneliness on Cognitive Health

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In this episode we're going to discuss a topic that's increasingly recognized as central to cognitive health and social connection. We'll define what it is and what happens when it's missing. Social isolation and loneliness are now widely discussed as public health concerns, and evidence has really mounted that social disconnection has profound effects on health, including cognitive decline and dementia risk. To help us think through this, we're joined by Dr. Ashwin Kotwal, a geriatrician and health services researcher at UCSF and the director of the Social Connections and Aging Lab. His work examines how social relationships shape aging related outcomes, including cognitive health, disability, and mortality. 

More resources

Additional Links:   

Ashwin Kotwal Faculty Profile 

Social Connections & Aging Lab @ UCSF 

Relevant Articles:  

Kotwal AA, Cenzer IS, Yaffe K, Perissinotto C, Smith AK. End-of-life health care use among socially isolated and cognitively impaired older adults. J Am Geriatr Soc. 2023 Mar;71(3):880-887. doi: 10.1111/jgs.18131. Epub 2022 Nov 23. PMID: 36420540; PMCID: PMC10023302. 

Kotwal AA, Allison TA, Halim M, Garrett SB, Perissinotto CM, Ritchie CS, Smith AK, Harrison KL. "Relationships, Very Quickly, Turn to Nothing": Loneliness, Social Isolation, and Adaptation to Changing Social Lives Among Persons Living With Dementia and Care Partners. Gerontologist. 2024 Apr 1;64(4):gnae014. doi: 10.1093/geront/gnae014. PMID: 38499400; PMCID: PMC10948338. 

Kotwal AA, Cenzer I, Hunt LJ, Ankuda C, Torres JM, Smith AK, Aldridge M, Harrison KL. Psychosocial distress among spouses of persons with dementia before and after their partner's death. J Am Geriatric Soc. 2024 Aug;72(8):2336-2346. doi: 10.1111/jgs.19030. Epub 2024 Jun 1. PMID: 38822746; PMCID: PMC11323186. 

Transcript

Lauren Gerlach:

Welcome back to Minding Memory. Today, we're going to discuss a topic that's increasingly recognized as central to cognitive health, social connection. We'll define what it is and what happens when it's missing. Social isolation and loneliness are now widely discussed as public health concerns, and evidence has really mounted that social disconnection has profound effects on health, including cognitive decline and dementia risk.

Social isolation has also been linked to higher rates of cardiovascular disease, depression, disability, and mortality. In fact, the health impact of being socially disconnected has been estimated to be comparable to smoking up to 15 cigarettes a day and greater than the risks associated with obesity or physical inactivity. Importantly, it isn't just about feeling lonely.

It's about measurable changes in health and functioning. And this conversation feels especially timely. We're living in a moment marked by significant social disruption, polarization and a sense of disconnection that many people are feeling in their everyday lives. In that context, understanding how social connection shapes brain health and how repairing and strengthening those connections might protect it has really never felt more important.

Matt Davis:

I'm Matt Davis.

Lauren Gerlach:

I'm Lauren Gerlach.

Matt Davis:

And you're listening to Minding Memory.

Lauren Gerlach:

So as our population ages, these questions sit at the intersection of dementia research, prevention and care. And to help us think through this, we're joined by Dr. Ashwin Kotwal, a geriatrician and health services researcher at UCSF and the director of the Social Connections and Aging Lab. His work examines how social relationships shape aging related outcomes, including cognitive health, disability, and mortality. Ashwin, welcome to Minding Memory. We're so glad to have you here.

Ashwin Kotwal:

Great to be here. Thanks for having me.

Matt Davis:

So to start things off, we were wondering if you could tell our listeners a little bit about your background and what got you interested in studying social connection.

Ashwin Kotwal:

Sure. Yeah. So my background is in geriatrics and palliative care. So I did a combined geriatrics and palliative care fellowship here at UCSF after my internal medicine residency. And what drew me to this space was really my clinical experiences. As I was going through training, we learned a lot about how to provide really good medical care to people, how to think through people's priorities, align with their values, provide really good end of life care around addressing symptoms.

But what I noticed over and over again was that loneliness or isolation, they kept coming up and they were really a fundamental source of suffering as people aged and experienced serious illness. And so while I had these really good tools to address their medical needs, I felt like their social needs were kind of falling through the cracks and really affecting our ability to address their quality of life. And so that really drew me, this kind of clinical need, this issue that really bothered me. And I learned that there has been a lot of work in this space and a lot that we as clinicians could learn and kind of apply to the people we were seeing day to day.

Lauren Gerlach:

And just to make sure that we're all using the same kind of language and terminology, can you tell us a little bit about how you distinguish social isolation from loneliness or how those things are related?

Ashwin Kotwal:

Yeah, that's so important and it comes up all the time. So the way I think about these concepts is that they're related but distinct factors. So loneliness refers to that subjective feeling that your social relationships are lacking. So that feeling of lacking companionship, you feel left out. A common phrase, for example, is that you can feel lonely in a crowd. So you might be surrounded by other people, but still feel lonely. And that's really important because you can't know if someone is lonely unless you ask them.

And there are a lot of different ways of asking people, whether it's standardized scales or just simply asking, "How often do you feel lonely?" So that subjective component is really key here. And then on the other side is social isolation, which is a more objective deficit in the number of relationships that you have or the social roles that you may have or the frequency of contact with others. So how many children do you have, friends, how many family members?

How often are you going to church, religious activities, clubs, group activities? So you can imagine it gets pretty complicated quickly once you start tallying all those relationships up and the frequency of interaction with others. So these can be much longer complex scales. One of the things I use though is who are the people in your life that you can talk to about important things? And if people have trouble naming even one person, that might signify that they're really isolated. They really have no one else to turn to.

Lauren Gerlach:

And when you kind of look across the population or studies, kind of how frequent is social isolation or loneliness among older adults?

Ashwin Kotwal:

It's more common than you'd think. When I first saw the prevalence estimates, it was pretty shocking. So some of the national studies from the Health and Retirement Study and others have found that the overall prevalence of loneliness is about 40%. So 40% of people on occasion feel lonely. And then about one in 10 older adults frequently feel lonely. So when you ask them about loneliness, they say, "I often feel like I lack companionship, lack belongingness, feel isolated from others."

When you look at social isolation, it kind of depends on the threshold that we use to define isolation. When we've used scales developed from the Health and Retirement Study and other cohorts, when we use pretty strict thresholds -- so not living with others, being unmarried, having less than monthly interaction with friends, family, and minimal community participation in volunteering, religious activities, other social participation. So pretty strict threshold here. We see about 10% of older adults meet that criteria for social isolation. But yeah, it can depend on the scale that you use and the threshold that you deem as meaningful.

Lauren Gerlach:

And are there certain populations of older adults who are particularly at risk?

Ashwin Kotwal:

Yes, absolutely. So serious illness is a big factor here as clinicians that we can think about as amplifying both the risk for loneliness and isolation as well as this impact. So for dementia, for example, about a quarter of individuals, so 25% of people meet criteria for frequent loneliness, that's compared to 10% in the general public.

And then similarly, about 25% meet criteria for social isolation, even using that strict threshold. And it's important to note that even though it's a quarter for each, it's very few people that experience both. So the correlation between these two factors, the correlation coefficient is like 0.1. So only a few percentage of people are experiencing both.

Matt Davis:

So you mentioned the literature on this. I'm just curious, I mean, the first time I became aware of this was some of the studies coming out during COVID, looking at isolation among individuals living in nursing homes. But does the literature go way back or has it been only studied in the last couple of decades?

Ashwin Kotwal:

Yeah, great question. The pandemic really did bring this into the forefront in the clinical world, both clinical visits we were seeing day-to-day, as well as the research I think really exploded after the pandemic, but this does build on a foundation of research that goes back several decades.

And I would say that the fields of sociology, social psychology, social epidemiology all have thought a lot about these concepts and developed a lot of the conceptual frameworks and scales that we use in this space. So there is a lot of foundational work and there's a lot of work that still needs to be done to adapt some of those ideas to the clinical space where we're really trying to have a direct impact and we're much more intervention focused.

Matt Davis:

Could you talk a little bit about sort of the relevance specifically to the population of older adults living with dementia?

Ashwin Kotwal:

Yeah. So this is a really important area of study. And building on our last comment around how long this has been going on, there's really been quite a bit of research in this space that focuses on two buckets. The first is social isolation or loneliness, are they risk factors for the development of dementia? So can we modify or enhance social connection in order to reduce our risk of cognitive decline or dementia in the future?

That's probably where a majority of the research has focused on. And then the second bucket focuses on people who are living with dementia or cognitive impairment and ask, "Can we improve quality of life for people experiencing this condition by enhancing their social connection?" And that's an area of research that has been where my work has predominantly focused.

Lauren Gerlach:

And can you tell us a little bit more about that relationship between social isolation and cognitive decline? So is there any thought about what the mechanism is linking those?

Ashwin Kotwal:

Yeah. So I'll talk first about that first bucket of research, is social isolation a risk factor for cognitive decline? And so this is something where large population-based studies have consistently found that yes, it is a modifiable risk factor. And this draws from studies that have longitudinal follow-up of multiple decades from global cohorts, so kind of all around the world where they've looked at this over time, and it includes different measures of social isolation as well as pretty robust measures of cognitive decline as well, including even imaging and other measures.

So this is quite robust. And when we think about the comparison between social isolation as a risk factor to other modifiable risk factors is just as strong or stronger than many of the other known factors. So the Lancet report, for example, that was published on several, the 14, I believe, modifiable risk factors for dementia found that social isolation was one of the strongest. So if you address social isolation, you can prevent 5% of dementia cases worldwide, which is pretty massive.

It was similar to addressing education in early life. So this is a huge effect and it's a robust effect, it's consistently being shown, and there is a lot that we don't know. So I'll just say that there's several mechanisms that they think are going on here. One is called the use it or lose it hypothesis, which is you got to use these complex social functions in order to preserve them. A second one is called the cognitive reserve hypothesis.

And I think we hear about this in many other spaces in dementia research, but really this idea that when you develop complex social skills, it might buffer or protect from the pathologic changes people experience as they age, so like things like amyloid and other pathologic changes in the brain. Some researchers also refer to this as social cognition, which is kind of that ability to manage our social functions, interact with others, understand what others are thinking in order to have appropriate social interactions.

And then a third theory is this idea of avoiding stress related cognitive decline. So when you're lonely or isolated, it sets off these stress pathways in your body, the HPA axis, which can lead to chronic inflammation, kind of wear and tear, which affects our brain health. So many different reasons for why social connection can affect our brain health, and this draws on pretty robust population-based evidence.

Lauren Gerlach:

And once someone's living with cognitive impairment or dementia, how does social isolation or their social networks tend to change?

Ashwin Kotwal:

Yeah. Dementia, like a lot of neurodegenerative diseases is one that requires constant adaptation. I think that's what we've found from our studies is that even when you figure out how to adapt to what you're experiencing, things can change. And so it's important to consider the full trajectory of dementia when we're thinking about how it impacts people's social lives. So for example, early on, when people are really aware that their cognition is changing, that their memory is changing, their ability to navigate complex social situations is changing, right? That social cognition that I mentioned before. 

So that might impact how people approach their relationships. They may experience stigma or shame around the cognitive changes. They may withdraw from others. As it progresses, as dementia progresses, they may start to experience some of the early signs that we see clinically, things like apathy, functional challenges that prevent kind of independent social interaction. And then later, the behavioral challenges can be really challenging, inappropriate social behaviors, things like difficulty with executive function or memory challenges, which can really impact our social skills.

And so it's really, these things are changing all along the trajectory and people are trying to adapt as they go. And it's important to realize that dementia doesn't just affect the person living with dementia, but also their spouses, care partners, their surrounding social networks. People may experience anticipatory grief, loneliness many years before some of the changes that we think about clinically. So the bereavement process is quite complex and something that we can address, we can really intervene on.

Lauren Gerlach:

And I think some of your work looked also at care partners and caregivers and kind of how their social network or isolation may change over a patient's illness trajectory as well. Can you speak a little bit to some of the work in that area?

Ashwin Kotwal:

Absolutely. Yeah. We're really interested in the impact of dementia on surrounding social networks, particularly the spouse or care partners. So what we found is that in large national studies, when you compare people who are married to persons living with dementia, to people with other serious illnesses, those spouses tend to have nearly double the rate of loneliness, much higher rates of depression, although these are kind of distinct factors. And these rates remain high even before the death of their partner.

So people are experiencing anticipatory grief, changes in major disruptions in their overall social network. And I think this is a large source of suffering for people as they're experiencing the disease. So I think important to know that the impacts of dementia extend beyond the person living with dementia. And what we found is that there are a lot of adaptations that people are coming up with to address these needs.

Spouses, when we've done qualitative interviews, have mentioned things like support groups, shared spaces where you can address this stigma, the behavioral challenges that come up. They describe shared social activities. They really appreciate when clinicians bring this up and talk about it, even when there's no clear solution. They just want some space to discuss what's going on. And I think this is... and really, it shows an opportunity here to innovate and find ways to address these needs in order to improve quality of life.

Matt Davis:

So what do we do about it? Based on your experience, what interventions seem to show promise?

Ashwin Kotwal:

Yeah. The intervention space is one that's pretty new. It's an emerging area. I think the existing research has done a really good job of showing it's a problem. And now, similar to many other research fields, the push has been, how do we actually address this? I think some of the prior work can inform our approach to addressing loneliness or isolation among people living with dementia as well as their care partners. So things like asking about loneliness, just identifying that social need and providing space can often be therapeutic.

I found as a clinician that we don't have to have the solution in hand in order to provide that space for people to discuss it. And I've often found that when you do that, people feel a sense of relief. They feel a sense of that burden being lifted just by being able to talk about it. The second thing I do as a clinician is I try to work with people to think through what might help them, brainstorm, what do you think is contributing here? What do you think might help? And also have a little bit of a sense of the available resources that might be able to match their individual needs.

So I'm thinking about things like support groups, there are telephone companionship lines, there are peer interventions, which I think is especially relevant to dementia where care partners might find peers who have a wealth of experience providing caregiver support to others. And then I also think about the ancillary services, these external support services that we can mobilize in order to help people, especially those who are fairly isolated, things like home care services, volunteer support networks, even when people are approaching the end of life, starting hospice early.

So you get these services in people's homes early so that they're familiar with them and they're able to kind of bridge some of those gaps and care needs. So there's a lot that we can do and there's, I think a structured approach we can take clinically. Now from a research standpoint, I think a lot is needed in order to figure out what works here that we can adapt from prior interventions.

How should we innovate here? How should we think about the full trajectory of the dementia illness? What are the components of people's social relationships that we can really modify and make the biggest difference here? So there's a lot we can do from a research space, but I don't think that should keep us from trying to make an impact in real time.

Matt Davis:

It's amazing you get into some of that with your patients. I'm just imagining some folks probably are surprised the types of things that you're asking and inquiring about in your clinic. It's great.

Ashwin Kotwal:

Yeah. What I found is that when you bring these things up, sometimes people are a little surprised. The patients and family members are like, "Oh, thank you for bringing this up." And they really appreciate you making space for this. This can build relationships, it can form a lot of trust, and it can change the whole way that we have conversations with people. Because once you start making it a priority, it can kind of feed into everything that you discuss.

You're talking about medication changes, well, you're doing it in order to help them engage with the rest of their social life. So that helps to frame some of these trade-offs, for example, between antipsychotic use and some of the side effects. When you're thinking about hospice, that can be a really difficult conversation to have with people, but when you think about some of the social aspects that hospice can help with, that can really make a difference in how people weigh those trade-offs. So yeah, it really just opens up a different angle of having conversations here.

Lauren Gerlach:

And thinking about your kind of research work, what are some of the things that you think the field still really needs to fundamentally understand or what would be some of the things that would help move the science forward?

Ashwin Kotwal:

Science could be moved forward in so many different ways. And so I really encourage early career researchers to get involved and to think about what motivates them in terms of why they want to make a difference in this space. Some of the things that come to mind for me are measurement challenges. So really understanding what we're measuring makes a big difference in terms of how we compare our findings to the rest of the literature, how we track improvements over time.

And for people living with dementia or experiencing cognitive impairment, we can use the existing measures, but I think we might be missing some of the nuance here as to what are the contributors to loneliness, what are the key social relationships that matter among people with dementia? I'll give you an example that many of the social isolation skills that we use kind of similarly weight all of these different relationships when we kind of tally everything up.

And that might not be the right thing to do here, right? So I think there's a lot of nuance here with the measurements. Another challenge with measurement is we assume that people with dementia can't accurately respond to questions about loneliness. And what I found clinically is that's not the case. We can really learn a lot and there's both verbal and nonverbal signs of that emotional distress. So measurement is a big issue. I think mechanisms are a big issue here.

Thinking about how is social connection a risk factor for dementia. I want to know more about when should we be intervening here, how should we be addressing these different social relationships in order to impact dementia. And then from the quality of life standpoint, I'm interested in how are all of these different psychosocial issues intertwined? What is the pathway linking depression to loneliness and vice versa? And how does that impact quality of life among people with dementia?

So there's a lot of kind of mechanisms to unpack here, which could inform interventions. And so interventions that are, I think, top of mind for so many people right now and really being thoughtful about how can we meaningfully adapt existing interventions to people with dementia and how can we innovate and create new ways, both from our health system, as well as community-based organizations and other resources to address these needs. So lots of opportunity here and a lot of, I think, energy and enthusiasm in this space that make it a really exciting area to work in.

Matt Davis:

So I'm an introvert. Is there a bare minimum of social interaction required to avoid the negative consequences?

Ashwin Kotwal:

Yeah. It's funny because whenever I talk about this issue, the introverts in the room always raise their hand and they're very interested in this question of personality types that just kind of change how we navigate our social lives throughout our lifespan. And this also came up quite a bit during the pandemic when I think introverts rejoiced around the lack of pressure to socially interact, maybe got a little too comfortable.

Matt Davis:

Oh, it was great.

Ashwin Kotwal:

Yeah. So when I think about the relationship of social connection to health among people who are introverts or who might prefer a little bit of solitude to constant engagement, I think a lot about the mechanisms here. So what is it about our social connections that's impacting our health? So part of it is when you're around others, you just tend to be healthier, you have healthier behaviors, you exercise more, you have less substance use, you receive more emotional support from people who are around you.

So kind of thinking about what is the minimum in order to achieve those types of needs that might influence how people think about the threshold for introversion versus not. If you're already doing a lot of those healthy activities on your own, that's a great thing, but you need to be mindful about that and have some of that internal drive.

The other major mechanism I think about is who is there to support you during a crisis? So if you're really isolated, you enjoy living in solitude, that's fine, but you need to have somebody to turn to if things go poorly. If you lose your job, you cannot rely on your solitude in order to pay your rent every month. If your house is on fire and you can't get off the floor, your solitude won't help you in that situation.

So really think about those crises that come up, that inevitably come up as people age and how can you make sure that you have those necessary social resources in order to navigate them. And that's why just being aware, making it a priority early on is important. I often talk about prevention is much easier than addressing it later on. So prioritize your social relationships early in your life because it's harder to make really meaningful social relationships or like reconnect with long-lost family members later on when these crises come up.

Matt Davis:

It makes me wonder though about like the difference between individuals I know with small social networks versus large and maybe it's more about the quality and just having people in general, not necessarily the size of it, would you say or?

Ashwin Kotwal:

Absolutely. Yeah. The structure and the makeup of people's social networks is really important when we think about the impact on cognition. So for example, people may have small, really family oriented social networks that are very interconnected, people are kind of all talking among one another. Some of the terms that we use for this are “dense social networks” where people kind of know about one another. I think another term that's used is “bonded networks”, kind of network bonding.

So what people have found, other researchers have found is that when you have really dense interconnected social networks, that's actually bad for your cognition or at least a bad sign of your cognition. I kind of think of it as all your friends and family members are kind of talking about you because you need help navigating whatever issues you're going through. Right? And this is compared to when people have social networks that are really diverse.

So it's not just family members, they have friends, they have professionals that are not really talking amongst one another. And that person themselves is the bridge for all of these different networks that are surrounding them. And that might be a good sign because it shows that you are able to navigate these really complex social networks.

You're actually a center point in that and that it's forcing you to kind of engage in some of these more complex social and cognitive tasks. So the size and the makeup of your social network is really important here. And that probably falls into the category of like how to reduce your risk for future dementia. Because I will say that if you are experiencing dementia, having a very dense interconnected network is probably a good thing. You're probably less likely to fall through the cracks.

Matt Davis:

So is there anything that we haven't covered that you want listeners to know?

Ashwin Kotwal:

I think we've been pretty comprehensive here. This is a big space. I think two major points. The first is not to get overwhelmed with the space here. This is one that is highly collaborative, draws on the expertise of so many disciplines. There's a lot of terms that are out there, especially when you start to delve into the literature here. But this is fundamentally just a very human experience. And it's one that's often best told through stories and our personal experiences.

And so I'd encourage listeners who are interested in the space to not get overwhelmed by the literature, but instead to think about what motivates them in terms of addressing this. And there's a lot of great communities of people that are highly collaborative and want that energy and enthusiasm in this space. So the American Geriatric Society has been a great advocate in this space. Gerontological Societies of America has an interest group here that has over a hundred members.

So there's just a ton of interest and collaboration here. So that's the first. And then the second is that there's just so much work on social connection as a risk factor. And our main point for much of my lab's research is that it's not just a risk factor.

It's an important outcome in and of itself. It's one of the most important person centered outcomes when we talk to people and their family members and consistently. So there are many things that we can do as clinicians, as members of society that can really improve people's social connection. So the more we can make it a priority, I think the better we're all off.

Lauren Gerlach:

Thank you so much for joining us today.

Ashwin Kotwal:

Thanks for having me.

Matt Davis:

If you enjoyed our discussion today, please consider subscribing to our podcast. Other episodes can be found on Apple Podcasts, Spotify, and SoundCloud, as well as directly from us at capra.med.umich.edu, where a full transcript of this episode is also available. On our website, you'll also find links to other resources we've created specifically for dementia research. Music and engineering for this podcast was provided by Dan Langa. More information is available at www.danlanga.com.

Mining Memory is part of the Michigan Medicine Podcast Network. Find more shows at michiganmedicine.org/podcasts. Support for this podcast comes from the National Institute on Aging at the National Institutes of Health, as well as the Institute for Healthcare Policy and Innovation at the University of Michigan. The views expressed in this podcast do not necessarily represent the views of the NIH or the University of Michigan. Thanks for joining us and we'll be back soon.