Physical and Social Environment Relationship With Sleep Health and Disorders

Adult Sleep and the Environment

Physical Environment and Adult Sleep Health

Exposure to a natural physical environment has been associated with better sleep health. Observational studies have shown that adults living in neighborhoods with access to green space or natural water features have a lower likelihood of insufficient sleep. Green vegetation has been associated with better cardiovascular biomarkers and lowers sympathetic activation.8 tree canopy was associated with longer weekday sleep duration in a survey study in Wisconsin. These natural environment features are more common in suburban and rural neighborhoods. Green space may promote walking and other healthy behaviors, lower stress levels, and improve mental health which could facilitate healthy sleep. Other environmental features unique to rural living have not been well studied in relation to sleep.

Built Environment and Adult Sleep Health

Prior epidemiologic research has identified an association of built environment features with obesity and cardiovascular and metabolic disease. Geographic information system (GIS) data demonstrate that lower mixed land use and higher density of fast food outlets are associated with obesity. These neighborhood obesogenic features could foster sleep apnea by promoting weight gain and sedentary behaviors. Studies have found that residential features promoting physical activity and healthier diets are associated with a lower risk of incident diabetes14 and weight loss. Because obesity is an established strong risk factor for sleep apnea, living in neighborhood environments that foster obesity may contribute to the risk of developing sleep apnea. Features of the built environment, such as street connectivity, parks,, and recreational facilities, and bike lanes, can promote activity; these same features may also influence sleep-disordered breathing. Walkability is higher in neighborhoods with sidewalks, traffic calming, pleasant aesthetic features, and social and recreational destinations, Neighborhood walking environment, assessed via survey, has been associated with sleep apnea independent of individual sociodemographic characteristics. Residing in a neighborhood with a less favorable walking environment (rated in the lowest 25% of neighborhoods) was associated with 2.7 events/h higher apnea-hypopnea index (AHI), more substantially in those with obesity. The greater actigraphy-measured activity was associated with 3.4 events/h lower AHI in men, partially mediated by BMI, independent of age, race/ethnicity, comorbidities, education, and income. Exercise has been associated with reduced incidence and lower severity of sleep apnea.19 It is hypothesized that exercise reduces lower extremity fluid accumulation; sedentary behaviors lead to rostral fluid buildup and the subsequent upper airway narrowing once supine and the fluid shifts.20 Therefore, built environmental features that promote physical activity may reduce sleep-disordered breathing severity.

Neighborhood Disadvantage and Adult Sleep Health

Neighborhood disadvantage refers to a summary measure of the socioeconomic features of the neighborhood residents and is often calculated using census data such as high rates of poverty, female-headed households, unemployment, public assistance, and low homeownership. Neighborhood disadvantage has been associated with increased odds of restless sleep in women,22 and longer wakefulness-after-sleep-onset (WASO) among urban-dwelling adults.23 In a twin study, area deprivation, a measure of neighborhood disadvantage, was independently associated with shorter sleep duration.24 However, other studies have shown no association between neighborhood disadvantage and sleep duration, sleep quality, or latency. Sleep duration differences were associated with neighborhood social environment rather than SES in models adjusting for individual sociodemographics, comorbidities, and health behaviors in one study including participants from Los Angeles, California, and New York, New York, neighborhoods.25 Inconsistent findings across studies may reflect the correlation of disadvantage with other causative neighborhood social factors contributing to sleep health such as the development of trust, social ties, and collective efficacy.

Social Environment and Adult Sleep Health

The social environment can foster perceptions of safety and social support and can affect mood, anxiety, and stress, which can contribute to a state of arousal and potentially impact sleep. More specifically, an unfavorable social environment can contribute to sleep deprivation, insomnia symptoms, and circadian disruptions (eg, delayed sleep timing).32 The social environment includes perceived, often questionnaire-based, measurements of social connections/cohesion/ fragmentation, stigma, safety, violence, and crime. The social environment can also be objectively assessed using GIS, census data, and criminal records. The social environment is enmeshed within the socioeconomic/ racial/ethnic characteristics of the neighborhood and is associated with built environmental features, often with unfavorable features in more than one domain. For example, neighborhoods with a lower perception of safety have greater deprivation and disorder.

Living in communities with greater social cohesion is associated with better sleep health such as higher actigraphy-measured and self-reported sleep duration.26,33 Social cohesion reflects high levels of relationships, trust, and community spirit in a neighborhood. Cohesive neighborhoods have less crime, higher perceived safety, and greater social capital. Conversely, social fragmentation, the underdevelopment of connections between community residents, has been associated with shorter sleep duration, lower sleep quality, and greater sleep difficulties across diverse populations including underrepresented minority groups such as blacks, Hispanic/Latinos, and Native Hawaiian and Pacific Islanders

Ambient Environment and Adult Sleep Health

Ambient features (light, noise, air quality, humidity, and temperature) are often correlated with built features such as urbanicity, population, and intersection density with more detrimental ambient features in denser urban areas. The ambient physical environment is also often patterned by SES and race/ethnicity, that is individuals of lower SES and minorities may be more likely to live in environments that have more pollution (ie, air, noise, light) and greater density.

A prominent feature of urban environments is exposure to artificial light. Light pollution resulting from street and commercial building lights can produce inopportune light exposure at night, which may cause delayed sleep onset. Light affects circadian rhythms; exposure to artificial bright light during the nighttime can suppress melatonin secretion and can delay sleep onset. Higher exposure to inopportune light is associated with prolonged sleep latency, circadian phase delay, and insufficient sleep.

Author: Martha E. Billings, MD; Lauren Hale, Ph.D.; and Dayna A. Johnson, Ph.D., MPH