Session Addresses Environmental, Social Determinants of Sleep Health

During a session presented at Virtual SLEEP 2021, the 35th annual meeting of the Associated Professional Sleep Societies LLC, experts highlighted research on social and environmental determinants of sleep health and their implications on health disparities.

“Sleep health in the United States significantly impacts the nation’s public health and economy, increasing the risk of mortality by 13% and costing over $400 billion each year,” explained Janeese Brownlow, PhD, an assistant professor of neuropsychology at Delaware State University and chair of the session. Brownlow is also the director of the Sleep Stress and Behavioral Neuroscience Program at the university.

Past research has illustrated the bidirectional relationship between sleep health and other conditions including obesity, diabetes, depression, and anxiety disorders, among others.

The session dove into both internal home and external environmental factors that contribute to poor sleep health. Often, these social and environmental factors can be broken down by socioeconomic status (SES) or by race or ethnicity.

Race and Sleep Health

Describing the social ecological model of health, for a person nested within multiple levels, these levels influence individual behaviors and abilities to adhere to different treatments and recommendations in terms of intervention strategies, said Dayna Johnson, PhD, MPH, MS, an assistant professor in the Department of Epidemiology at Emory University, during her presentation.

In other words, individuals’ sleep behaviors can be affected by a multitude of factors including living conditions, neighborhood environments, and social and economic policies.

While residential segregation, socioeconomic conditions, and neighborhood environment can all have an effect on sleep in the environmental context, neighborhood environments can also promote psychosocial factors including experiences of discrimination, microaggressions, and increased stress, Johnson explained.

Furthermore, areas with high noise pollution, inopportune light exposure, and that are unsafe can inhibit individuals from achieving good sleep health. Some of these environments “resulted from different discriminatory laws, such as redlining and certain individuals, such as racial minorities and immigrants, were placed in these environments and are exposed to these different effects,” Johnson said, adding these areas also often lack resources, such as access to health food.

Inconsistent work schedules, or individuals having to work multiple jobs due to low minimum wages are also detrimental to individuals’ sleep health.

“Sleep has been shown to vary in the past by industry of employment among US workers and work is believed to be connected to sleep through, for instance, extended work hours, rotating or night shift work, impaired work-life integration, and job-related emotional as well as physical stress,” said Chandra Jackson, PhD, MS, a researcher at the National Institute of Environmental Health Sciences, in a separate talk during the session.

But all “these different factors can individually or cumulatively lead to sleep deficiency, sleep disorders, circadian misalignment, and the adverse consequence is adverse physical and mental health outcomes,” Johnson said.

Citing data gleaned from the Multi-Ethnic Study of Atherosclerosis (MESA) Johnson and colleagues found “for a unit increase in the social environment, it was associated with sleeping almost 10 minutes longer on average.” Broken down by racial/ethnic groups, stratified analyses revealed “these associations were only present among Black African or African American participants…For Black individuals living in a better social environment, [this] was associated with sleeping around 12 minutes longer on average,” she said.

An additional study using sleep actigraphy showed low social cohesion was associated with worse sleep outcomes. Another study targeting specific barriers to adequate sleep health found safety concerns were common. These concerns ranged from being afraid of the dark, to fear of someone breaking into a bedroom window.

Overall, data indicated individual environmental factors alone were not preventing healthy sleep, “but the combination of these factors together in terms of overall score, were associated with shorter sleep duration.” In particular, adverse sleep environment scores were associated with approximately 109 minutes less sleep on average.

“The social neighborhood and household environment shape sleep health, so it's important to target interventions at these levels,” Johnson concluded, adding conducting more longitudinal studies to collect objective measures of sleep across demographic groups will be necessary to address disparities.

According to review results, health promotion programs implemented in the workplace may help increase employees’ sleep duration, said Jackson. But current race and ethnicity data regarding these interventions are lacking. “There's a lot of room for improvement since it's rather difficult to assess and understand the determinants of disparities if the data among minoritized groups remain sparse,” she said.

Compounding the issue, historically, laws and policies have systematically excluded populations identifying as Black, indigenous and people of color from the workforce. “In terms of history and labor market segregation, a particularly strong example would be Black people in this country being enslaved with no control over job demands and being systematically denied payment for labor despite living in a capitalist society,” Jackson said.

Research also indicates the work-sleep relationship may differ between Black and White adults as African Americans are more likely to have long working hours, to report general job stress, to experience objective and perceived discrimination, and to work in low-control high-demand positions with low decision-making power, Jackson explained.

“Blacks or African Americans are more likely to work multiple low wage jobs, to live in poverty despite being employed, to live in disadvantaged, under-resourced residential environments…and to have less well-connected professional networks to provide financial, emotional, and informational support.”

Enhanced income and employment opportunities through livable wages, earned income tax credits and worker protections could all prove beneficial to sleep health while also addressing disparities in sleep, Jackson concluded.

The Potential of Environmental Factors

In an additional talk, one presenter discussed his research investigating whether daytime temperature affects nighttime sleep quality. “We spend much of the day inside and for many office workers, the daytime hours are spent under mechanical conditioning,” said James Katungyi, MSSD, a PhD candidate at Carnegie Mellon University’s School of Architecture.

Although comfort is the main criterion for optimizing indoor temperature, Katungyi’s research goes beyond thermal comfort surveys and “aims to expand the criteria for evaluating and optimizing indoor thermal conditions.”

According to Katungyi, core body temperature provides one link between sleep quality and daytime temperature. “If a core body temperature profile is tuned to the environmental temperature profile, disruption in the environmental temperature profile might upset the core body temperature, which might be manifested in poor sleep quality,” he explained.

As mechanical conditioning flattens the environmental temperature for the daytime hours, it constitutes and environmental disruption. When building occupants are exposed to this disruption for a long period of time, it may compromise their well-being.

Katungyi outlined 2 experiments he devised to test these hypotheses, which will be conducted in the summer of 2021.

“The research draws parallels to research in indoor lighting. Lighting research has shown that variable lighting, which follows the natural patterns in luminance and color temperature, results in better sleep quality compared to static lighting,” Katungyi said.

“We need to examine temperature with the same rigor because temperature, like light, is circadian, and is a basic environmental condition…Exposure to natural environments or their imitations has often proven more beneficial to human wellbeing,” he concluded.