Dayna Johnson on How Racism and Poverty Contribute to Sleep Disparities

Siers-Poisson [00:00:05] Hello and thanks for joining us for Poverty Research and Policy podcast from the Institute for Research on Poverty at the University of Wisconsin-Madison. I’m Judith Siers-Poisson. Many of us suffer from not getting enough sleep from time to time. But for many people of color and those who are experiencing poverty, additional factors contributing to chronic poor sleep quality can have long term impacts on their health and well-being. For this episode, we’re going to be talking with Dr. Dayna Johnson about her ongoing work on sleep equity and how racism and poverty come into play. Dr. Johnson is a sleep epidemiologist and assistant professor in the Department of Epidemiology at the Rollins School of Public Health at Emory University. Her research is aimed at understanding the causes and health consequences of sleep health disparities. Dayna, thanks for joining us today.

Johnson [00:00:55] Thank you for having me.

Siers-Poisson [00:00:57] How widespread is the problem of either not being able to fall asleep or to stay asleep for the recommended time?

Johnson [00:01:05] So we have the phrase called “sleep health,” which spans several dimensions and including duration. So I’m distinguishing this concept because you said delaying sleep and interrupting sleep. Right? So sleep health is this concept that is really multi dimensional and includes sleep duration, timing, efficiency, quality, satisfaction and also regularity. So how regular your sleep is. So when we talk about sleep problems, we’re talking about interruptions in any one of those dimensions, right? And then there’s also sleep disorders which really get at what you asked about. So problems with initiating sleep or staying asleep. And so what we know is that poor sleep and sleep disorders are extremely common in society. So they’re really prevalent. And there are, depending on the sleep dimension or the sleep disorder, it can affect a large portion of our population. And so more specifically, we see that short sleep duration affects about 40% of U.S. adults. And depending on your race or gender or even where you live, sleep disorders such as sleep apnea can affect between — it’s a large range — between 4% and 80% of certain populations. Right. Very extreme. And then for insomnia affects about 30% of the population. And so all of these are very prevalent. And additionally, what I will point to as really a problem is that many sleep disorders are undiagnosed, which means they’re also undertreated or untreated. And so that really makes sleep problems and sleep disorders a public health crisis.

Siers-Poisson [00:02:58] And what are some of the health implications of not getting enough quality sleep?

Johnson [00:03:04] Yeah, so poor sleep quality is associated with a number of adverse mental and physical health outcomes. And so those include from depression to obesity, hypertension, cardiovascular disease, stroke, mortality, cognitive decline. And affects your overall quality of life. And so we really see that sleep is connected to almost every mental and physical health outcome.

Siers-Poisson [00:03:33] Clearly it’s a lot more serious than just needing an extra cup of coffee to get through your workday. Let’s talk about who is most likely to suffer from a chronic lack of sufficient sleep. In your research, have you found racial differences in who’s not getting the proper sleep?

Johnson [00:03:51] Yes. So we see that historically minoritized groups, specifically racial groups, African American or Black, Asian, Hispanic, Latinx, native Hawaiian Pacific Islanders, all have a worse sleep health. So shorter sleep duration, poor sleep quality and more sleep disorders in comparison to non-Hispanic White individuals. And additionally, we see these sleep disparities, is what we refer to them as, across the lifespan. And so particularly for these racialized minority groups, they have an earlier age of onset for sleep disorders and then a longer duration with these different sleep disorders. And so in terms of quantifying that difference, it really varies across the groups. But we see Native Hawaiian Pacific Islanders have more severe sleep apnea. Also, in terms of sleep duration, Black men have the shortest sleep duration in comparison to other racial and ethnic groups. And with that intersection of gender, with non-Hispanic White individuals, women in particular, having the longest sleep duration. And so there are clearly certain groups within that historically minoritized group — it’s heterogeneous, right — that are more at risk. But overall, we see that on average that they have worse sleep health and more sleep disorders, more severe sleep disorders.

Siers-Poisson [00:05:24] And what about differences by household income or experience of poverty or maybe educational attainment? Are there differences there as well?

Johnson [00:05:33] Yes. So that’s a little bit more complex. So in general, we see that individuals of lower socioeconomic status have wors sleep. Now, when we consider the intersection of both race and socioeconomic status, it’s a little different. And what I mean by that is we see for White individuals that as they increase in socioeconomic status, whether it’s education or occupation status, we see that the predictive probability of short sleep duration decreases. So meaning those of higher SES have a lower prevalence of short sleep duration or overall poor sleep health. Now, when we look at within Black or Latinx populations, we see the complete opposite. It’s actually those that are of higher socioeconomic status, higher occupations, those that are professionals, those with a college degree or higher, that have the worst sleep health. And in fact they have a shorter sleep duration, then lower SES Black or Latinx individuals. So, yes, it’s there’s really a difference, a gradient that we’re seeing that really points to the experiences of those that are Black or Latinx at a higher income education and occupation categories, which typically include discrimination, racism and unique stressors that they encounter that are impacting sleep at night or during the day if they work at night.

Siers-Poisson [00:07:17] And we’re definitely going to go more deeply into those ideas of how racism and discrimination can affect sleep health. But before we do, you use the term sleep equity in your work, and I’d like to ask you to share what that means for you and your research.

Johnson [00:07:32] Yes. So in the most simple way to define it, I think of sleep equity as this opportunity that is equal among all people to sleep, the opportunity to have healthy sleep, the opportunity to sleep, you know, just that equal opportunity. And so when we think about sleep inequities, we’re really talking about differences in those different dimensions of sleep health that I described that occur for designated populations like historically minoritized lower socioeconomic status that are due to factors that are unjust, unfair and preventable. So that’s really what we’re talking about when we think about sleep inequities.

Siers-Poisson [00:08:22] Going back to the issues of racism and discrimination, you studied whether experiencing what you call everyday discrimination has an impact on sleep and the role that stress caused by actual or perceived discrimination might have. What did you find there?

Johnson [00:08:40] Yeah. So in those studies we looked within Black individuals and measured their experiences with everyday discrimination. And we have some other papers where we looked at chronic stressors. And so the intention or the rationale behind that work is really understanding how Black individuals experience a stress that is additive to the stressors that we experience, everyone experiences in everyday life. So these are additive, unique stressors that likely have a physiologic effect. And so in that work, we looked at experiences of discrimination and how that was associated with sleep outcomes. And we found that Black individuals who had more experiences with discriminatory events or just overall discrimination, that they had a poor sleep quality and shorter sleep duration. And in this particular study, we were able to look across eight years and we saw that individuals who had an increase in their experiences of discrimination across time, they had poorer sleep quality over time as well. So changing from having a few to more had more of an impact on their sleep for the worse. And then for the chronic stressors paper, what we were really interested in understanding … so we looked at the burden of stress. So again, you know, everyone experiences stress. And so it’s a matter of is it a burden for you and what’s the effects on your health? And so in that study, we included both Black and White individuals. But we found that a chronic burden affected sleep for Black individuals only and not White individuals. So we’re seeing this burden of stress as a salient risk factor for poor sleep among Black individuals.

Siers-Poisson [00:10:48] So kind of keeping with that health or disease kind of terminology, we’re talking about chronic stressors. And in another study, you delved into another aspect of racism and its impact on sleep. And this might be more termed an acute event. It’s what you call extreme racism related events. How do you define those?

Johnson [00:11:10] Yes. So these extreme racism related events, it’s a scale. It’s a longer scale that is really capturing these experiences that are sometimes extremely violent and comprise different experiences, such as being chased because of your race, being called certain names, also being treated rudely, or someone disrespecting you. And then in that same scale, we also capture what we call vicarious experiences, which mean witnessing racist events happening to someone else and how that may affect you. So that vicarious experience. And so in that analysis or paper, we found that individuals who had more experiences with direct racist events or race-related events, they had a poor sleep quality. And so we use a well -validated measure of sleep quality in this study, and it was very much a linear effect. So as you saw the higher scores on that scale, so meaning more experiences with race-related events, we see that sleep quality actually decreases. So we had observed a poor sleep quality in relation to more experiences. Now that’s for the direct experiences of racism. So for the vicarious, it was similar in relation to sleep quality. So meaning, depending on where someone fell on this scale of vicarious experiences, consistently across it was poor sleep quality. And so taking all that together, we see that experiences with racism, and additionally, in a separate paper we looked at micro-aggressions, were all associated with poor sleep quality.

Siers-Poisson [00:13:12] Well, and I found it really interesting that when you were talking about those vicarious effects, that it’s not just maybe seeing someone else in real life, but, for instance, videos of police killings of African Americans, that that can have a huge effect. And if I’m remembering correctly, especially on Black women.

Johnson [00:13:33] Yes. Yes, that is correct. So this study sample was among Black women. And we’ve also done focus groups here in Atlanta with understanding these different findings in more detail. And what we’re hearing from women in particular is that they think about, you know, when they witness these events, again, whether it’s in person or through social media or the news, they think about how that could have been their brother, their fathers, their husbands and so on. And so we see that that has an effect. And so whether it goes through rumination, so witnessing these events and then consistently thinking about them, so ruminating at night can interrupt initiation of sleep and also can cause more wakefulness throughout the night. And so those are really dire consequences from witnessing such events. And so we did some focus groups during the pandemic. And so we were really faced with two major issues at that time. Right? It was, of course, the COVID-19 pandemic, which affects sleep. And we can talk about that. But also we were encountering a lot of civil unrest. Right. So we witnessed the murder of George Floyd. And so when we did our focus groups, the participants talked about thinking about that, thinking about how it could have been them. Right. And so that affects us, particularly affects Black women. And we see that it’s directly related to poor sleep quality.

Siers-Poisson [00:15:14] Well, and you just mentioned the COVID pandemic. And clearly that was a huge stressor and even a trauma for many people. And as we know, people of color were disproportionately affected by it. Have you been able to study that in the context of sleep equity?

Johnson [00:15:30] And so what we have looked at and my colleague and I wrote a commentary really outlining and describing how COVID-19 disproportionately affected sleep and health overall for Black individuals in particular. And so piecing together across a few studies that we’ve done and looking at COVID-19 on sleep, we saw that individuals, particularly Black individuals, were more likely to be affected negatively by COVID-19, whether it was from loss of wages, having a death of a loved one due to COVID-19. And so through some of our work, we found that insomnia severity — so again, insomnia as a condition in which there is a problem initiating or maintaining sleep — we saw that insomnia severity was worse for Black individuals in comparison to White individuals. So that was one finding. And so when we looked into understanding why that may be, why are we seeing worse insomnia for Black individuals in comparison to Whites? And we saw that it was due to one — racial discrimination explains some of that pathway. And then additionally, we saw that having stress due to COVID-19 also explain that that association. And so those stressors included those factors that I just mentioned, having a loss of wages or losing a loved one. In addition, it wasn’t studied in this particular study, but what we know is that particularly Black and brown individuals were more likely to be essential workers that did not have protections such as paid time off and other factors that could potentially mitigate some of the harm associated with COVID-19. And so those are just some of the factors that help to understand why we were seeing some of the associations that we observed. But overall, we did see that insomnia was worse for these populations. And again, I would say that although our paper was on COVID-19, you know, it’s hard to disentangle that from also, you know, the civil unrest that was observed during those times. So I really believe it’s a combination of all of those different stressors. And as you described, traumatic experiences that impacted sleep in different ways.

Siers-Poisson [00:18:15] I want to go back to the socioeconomic status for just a bit. I’m thinking about the challenges that low income folks might face, and I can see a lot of them affecting sleep. Some that come to mind are living in crowded conditions, maybe in densely populated neighborhoods, having unpredictable work schedules that might change when you’re able to sleep and even things like air quality or the lack of adequate heating and cooling. Are there other living conditions that might exacerbate sleep inequities?

Johnson [00:18:47] Yeah. So you’ve covered, you know, a lot of them in your question. So what we are finding is that individuals who live in what we refer to as sleep deserts, so these are areas that are not conducive to healthy sleep. They have worse sleep outcomes. And I distinguish between lower socioeconomic status individuals and sleep deserts for a few reasons. The main being that we see that Black individuals, regardless of their individual level income, are more likely to live in disadvantaged areas. And this is due to historic racist policies such as redlining, right? That has maintained certain communities to live in areas that were deemed unworthy of investment. And so with that being said, that means that we have some individuals that are not of lower socioeconomic status but are living in areas that are disadvantaged. And so these sleep deserts have all of those exposures that you mention. So more air pollution, more population density, also more intersection density, which is related to the air pollution, but also promotes more noise. And we know that noise is directly related to sleep and can impair sleep. And then also these environments can be a stressor. So environments that have more violence and more crime. And so there’s different pathways by which they affect sleep. So, for example, areas with more neighborhood violence tend to have brighter lights. And so that can really lead to inopportune light exposures for those that live in their homes that do not have blackout shades and also may not feel safe to wear a sleep masks to block those inopportune light exposures. Additionally, the violence and crime, in addition to being a stressor or, they ARE a stressor, and so then that can activate, you know, the HPA axis that can affect our sleep health outcomes for the negative. And so that’s, you know, just a few examples of adverse exposures in the environment that are contributing to poor sleep for certain populations that live in those sleep deserts.

Siers-Poisson [00:21:20] Going back to those health implications that you mentioned earlier, it seems like low-income people of color suffer from those conditions disproportionately. I’m wondering how possible it is to directly connect sleep inequities with those health inequities?

Johnson [00:21:36] Yes. So I will also say both low- and high-income Black and brown individuals are disproportionately affected by cardiovascular disease and its risk factors such as hypertension and diabetes. And so there are a few studies — this is still an area of research that is building — but based on the work that we have conducted, it does show that sleep duration and sleep efficiency explains some of the Black-White difference in cardio metabolic disease and and hypertension and also changes in blood pressure. And so there are some studies that have shown that Black men, in particular in comparison to White women, sleep duration explains 86% of the difference in diastolic blood pressure. Now, there are other studies that show about 50% difference. So in other words, if we intervene on sleep, we can reduce disparities in those health outcomes, particularly hypertension and cardiovascular disease, where most of that work has been conducted. There’s also some emerging data out of the cognition literature that showing that sleep and cognitive decline is an association that’s particularly pronounced among Black populations. So again, pointing to sleep as this point of intervention to reduce the burden of these adverse health outcomes.

Siers-Poisson [00:23:14] So, Dayna, I’m guessing that sleep inequity is not something that a lot of people have thought about if they haven’t dealt with it personally. Why does reducing sleep inequity matter to society as a whole?

Johnson [00:23:28] Yeah, that’s a really, really great question. And I think it’s fair to say probably many of us have not thought about our sleep and connection to these different health outcomes. I can say I didn’t until I started studying sleep and I understood how important sleep is to daily life as well as health outcomes. And so it’s important for us to again, go back to that idea and the data that shows us sleep is linked to pretty much everything, right? It’s connected to our mental and our physical health. And so the reason why sleep inequities are important and we should care about it is because it’s a likely intervention point. Sleep is a modifiable behavior that we can change, that can reduce adverse health outcomes. It could reduce the mortality rate, it can potentially enhance quality of life. And there’s data that’s supporting this. So by addressing sleep health inequities, we could also reduce the burden, the financial burden, economic burden on the health care system. And so, again, something that is modifiable is something that is treatable, that can help prevent other downstream health outcomes that can occur as a result of poor sleep health. And that’s in addition to just having a sleep justice or a health justice perspective, social justice specifically. And so we should not think about sleep as just a privilege. This should not only be awarded to people who are of a certain socioeconomic status that have been awarded certain privileges in life. The ability to sleep should be afforded to all of us. And just from a human perspective, this is something that we should achieve. And then in addition to those other things, like we can reduce the economic burden on the health care system, we can reduce downstream adverse health outcomes and potentially reduce health inequities overall. And so I talked about how sleep disparities are contributing to overall health disparities. So if we could intervene there and reduce sleep inequities, we may be able to make a drastic impact on the reduction of overall health disparities.

Siers-Poisson [00:25:59] So given all of those reasons why it’s a societal good to address sleep inequity, are there local or maybe higher level policy approaches that you’d see as advancing that sleep equity?

Johnson [00:26:13] Yeah, great question. So there’s a number of policies that we can consider. And so I talked about some of the economic benefits to addressing sleep inequities. The other piece is it can also decrease loss of productivity. So if we have a healthier workforce, right, especially individuals that are contributing to the automobile industry and other industries that are typically saturated with Black and brown individuals, you know, there are better outcomes in terms of productivity for employers. But if we go to thinking about these policies, so they’re workplace policies that can be in place in addition to societal. And so going to the larger one is minimum wage. So minimum wage is not a livable wage. And so individuals that have a minimum wage that may have a family are often working multiple jobs or they work rotating shifts. And so being a shift worker is a form of a circadian disorder which disrupts our sleep wake cycles and have adverse health outcomes as a result. And so if we can increase that wage, that can shape individual behavior. So, for example, you know, you can work one job and increase that opportunity for sleep, right? And then additionally, we can potentially resolve shift work disorder. So again, this circadian disorder that has a negative effect on our health outcomes. And so additionally, there’s what we call sleep hygiene or healthy sleep behaviors. And one of those factors is having a consistent sleep schedule. And so going back to that rotating shift work, if you’re constantly changing the times at which you work, you also are hindering your ability to implement a consistent bedtime for yourself. And then think about if you have children, you’re also likely going to affect that. And then the child can’t have a consistent bedtime. So that’s a structural factor that is affecting individual behavior. And so if you’re just focused on the individual, you miss that larger context. So it’s not that they don’t want to implement a consistent bedtime, it’s that the structural factor doesn’t allow for that. So increasing minimum wage is a great way to do that. Additionally, another policy that is really being pushed and implemented in several places is school start times. Now, this can benefit all people, but it can have a potential additional benefits on individuals in lower-income areas as well as those in rural areas. And so depending on the school start time, we see children are getting up as early as 5 a.m. to catch a bus, to go across the city or across the district in which they live to be able to go to school. And so that is not in line with their circadian rhythm. And we see that that impacts performance, academic performance. So, for example, there’s a study that showed that giving a child a test at 8 a.m. and giving them the same test at 10 a.m., they’ll perform better at 10 a.m. with no additional opportunity for learning. It’s just that they’re more awake at that time. And so having a policy around school start times is is important. And so we’re seeing that emerge. Healthy People 2030 has a goal that there are no secondary schools that start earlier than 8:30 a.m.. And so that’s just another example of a policy that can be implemented. And then, you know, a little bit more downstream, but still broader context, if we think about neighborhood environment, we talked about sleep deserts. And so if there are more regulations around traffic, which is related to pollution, which we know can cause inflammation of the airway and breathing and potentially increase risk for sleep apnea. And then also policies around manufacturing facilities when they’re noncompliant. So having more control around the pollutants that are being emitted from these different industrial plants, which again are the result of historic racist policies that place manufacturing facilities in the most disadvantaged neighborhoods. And so if we relocate these places or regulate the types of emissions that are occurring, we can reduce that negative effects on health, particularly sleep health, for individuals that are most at risk for living in these different areas. So I can go on and on, but those are great examples of policies and initiatives that we should be working towards that will not only improve sleep but improve overall health.

Siers-Poisson [00:31:51] Dayna, as we wrap up, what further research would you like to do or see done on the topic of sleep equity?

Johnson [00:32:00] So that’s a great question. So we are … so I’m an epidemiologist, which typically means that I study determinants and consequences of poor sleep. But I am also an emerging advocate for intervention. And so my research group is doing more interventions. And so we focus a lot at the individual level. And we have a mindfulness intervention that we just completed with focusing on decreasing stress and anxiety at bedtime to help with initiating sleep and helping people stay asleep. And so, again, that’s at the individual level. So what I am hoping to do is move more upstream to intervene at that neighborhood level. And so just for an example, my colleagues and I have a study where we are evaluating sleep before and after weatherizing homes. And so in the beginning when, or in the midpoint of our discussion, and you were describing neighborhoods, you talked about extreme temperatures. And so we see, you know, climate change is happening. And so one strategy may be weatherizing homes in order for our household to mitigate some of those adverse interactions, experiences with extreme heat, you know, through insulation and proper ventilation and so on. We are in the midst of that study so we don’t have results now, but it’s looking very promising that such an intervention at the household can potentially help to improve sleep. And then additionally, we’re trying to look at the neighborhood, and this is more at the start of trying to understand different ways in which that we can modify the neighborhood. And so in my work in sleep equity, it’s about not moving people. That is not the answer. The answer is improving the conditions in which they live, not for other people to move in and gentrify the neighborhood. But for the people who live there to benefit. So we’re just looking now to identify factors that we can change and working towards that, change the neighborhood environment and see what type of improvements there will be in one sleep.

Siers-Poisson [00:34:24] Well, Dayna, thank you so much for spending time with us today. I certainly learned a lot and you’ve given us a lot to think about.

Johnson [00:34:31] You are very welcome. Thank you so much for even having the idea to talk about sleep equity, which is so important. So I’m happy to be part of this and spread the word around sleep equity.

Siers-Poisson [00:34:45] Thanks so much to Dr. Dayna Johnson. She joined us to discuss her work to increase awareness around the importance of sleep and the connections between poverty, racism and sleep inequities, and to eliminate sleep health disparities. Links to some of her research that we discussed can be found in the show note for this episode. The production of this podcast was supported in part by funding from the U.S. Department of Health and Human Services Office of the Assistant Secretary for Planning and Evaluation. But its contents don’t necessarily represent the opinions or policies of that office of any other agency of the federal government or of the Institute for Research on Poverty. Music for the episode is by Poi Dog Pondering. Thanks for listening.