What keeps low-SES children from sleeping well: the role of presleep worries and sleep environment

Highlights

• Low-socioeconomic status (SES) children tend to have shorter sleep duration and more subjectively reported sleep problems.

• The reasons for this association are unclear.

• Presleep worries were found to account for some portion of the association.

• Some conditions of the physical sleep environment were also found to be intervening variables in the association.

Abstract

Objectives

Children in families of low socioeconomic status (SES) have been found to have poor sleep, yet the reasons for this finding are unclear. Two possible mediators, presleep worries and home environment conditions, were investigated as indirect pathways between SES and children's sleep.

Participants/Methods

The participants consisted of 271 children (M (age) = 11.33 years; standard deviation (SD) = 7.74 months) from families varying in SES as indexed by the income-to-needs ratio. Sleep was assessed with actigraphy (sleep minutes, night waking duration, and variability in sleep schedule) and child self-reported sleep/wake problems (eg, oversleeping and trouble falling asleep) and sleepiness (eg, sleeping in class and falling asleep while doing homework). Presleep worries and home environment conditions were assessed with questionnaires.

Results

Lower SES was associated with more subjective sleep/wake problems and daytime sleepiness, and increased exposure to disruptive sleep conditions and greater presleep worries were mediators of these associations. In addition, environmental conditions served as an intervening variable linking SES to variability in an actigraphy-derived sleep schedule, and, similarly, presleep worry was an intervening variable linking SES to actigraphy-based night waking duration. Across sleep parameters, the model explained 5–29% of variance.

Conclusions

Sleep environment and psychological factors are associated with socioeconomic disparities, which affect children's sleep.

Introduction

Sleep is increasingly being linked to multiple aspects of health and well-being in youth [1]. Experimental and observational studies have shown that sleep is critical to maintaining metabolic, endocrine, and immune functioning [2], and it is related to health-related behaviors such as decreased physical activity, increased risk of substance use, and suicidal ideation [3]. Other research suggests that daytime sleepiness is related to behavior problems and mood [4], to lower levels of self-reported general health [5], and to an increased risk of unintentional injury [6].

Given the important role of sleep for overall health, it has been proposed that differences in various sleep parameters along socioeconomic lines may explain, at least in part, health disparities for a number of diseases [7], [8]. This proposed link is underscored by research documenting socioeconomic disparities in sleep beginning in childhood. Studies on associations between family-level economic disadvantage and sleep have shown that lower socioeconomic status (SES) is associated with shorter sleep duration when assessed objectively using actigraphy [9], [10], [11] and through self- and parent-report methods [12], [13]. In addition to sleep duration, self-reported subjective sleep problems (e.g., trouble falling asleep, maintaining sleep, and oversleeping) may be associated with family SES. Findings from the National Sleep Foundation's 2006 [14] survey showed that adolescents with family income in the lowest bracket (<$50,000) were more likely to report difficulty falling asleep and staying asleep as compared to those in the highest bracket (>$100,000) [14]. Related research has found that, during late childhood, a lower income-to-needs ratio was associated with greater self-reported sleep/wake problems [9].

The reasons why youths from lower socioeconomic backgrounds are at a greater risk of shorter and worse-quality sleep have not been well studied, and there is a need to identify mechanisms linking lower SES to poorer sleep [15]. The physical sleep environment is considered an important domain of “sleep hygiene” [16]. The National Sleep Foundation's sleep hygiene recommendations include keeping the bedroom “comfortable, free from light and noise,” and these recommendations are supported by research showing links between the sleep environment and sleep problems. A study of families in China, for example, found noisy home conditions to double the risk of children experiencing more than three symptoms of insomnia [17]. Fewer economic resources may make it more challenging for families to maintain children's sleep environments that are quiet, dark, and kept at a comfortable temperature, however. Smaller domiciles, for example, make it more likely that young children will share a bedroom with siblings and tighter living conditions are associated with greater difficulty falling asleep [18]. Research has also found that children from lower-income homes are three to four times more likely than those from the middle- and upper-income brackets to have a television in their bedroom [19]. In a review of the literature, Cain and Gradisar [20] found consistent evidence that the presence of a television in the bedroom is related to shorter total sleep and higher levels of sleep disturbance. Therefore, it is possible that the sleep environment may be an important consideration when examining links between SES and sleep. Indeed, limited research suggests that the sleep environment may at least partially explain differences in sleep along socioeconomic lines. In a sample of adults, sleep environment factors were found to partially mediate links between SES and poor self-reported sleep quality in a diverse sample of adults [21].

Another possible mechanism that could link economic disadvantage and sleep is that lower-SES children's sleep may be compromised due to worries they have that prevent them from easily falling asleep. Nicassio, Mendlowitz, Fussell, & Petras [22] created the Pre-sleep Arousal Scale that separated arousal into somatic arousal (e.g., heart racing or stomach upset) and cognitive arousal (e.g., being distracted by sounds or worry about falling asleep). Associations between cognitive arousal at bedtime, including worry, and sleep disturbance have been demonstrated in children and adolescents. Alfano, Pina, Zerr, and Villalta [23] reported that greater cognitive (but not somatic) presleep arousal was associated with shorter sleep duration and more sleep problems reported by parents in an ethnically diverse sample of 7–14-year-olds. It is possible that youths who are economically disadvantaged experience greater levels of cognitive arousal as a result of greater exposure to daytime stressors. Economic disadvantage is associated with high levels of family stress and numerous specific stressors, including exposure to events that are unpredictable and uncontrollable, harsh discipline, and violence at home, school, or neighborhood [24]. However, no research has examined whether the higher rates of sleep disturbances in lower-SES children may be related to greater presleep worries in that population.

The aim of the current study was to explore novel possible mediators in relations between SES (as indexed by family income-to-needs ratio) and sleep in a community sample of children with a wide range of SES. Given the importance of examining multiple parameters via objective and subjective methods [25], sleep duration and quality (continuity/fragmentation and schedule) were assessed using actigraphy, and subjective sleep/wake problems and daytime sleepiness were assessed with a self-report questionnaire. Presleep worry and the sleep environment were examined with children's self-reports. We predicted that lower SES would be directly related to sleep and that both sleep environment conditions and greater presleep worries would function as mediating variables in the link between lower SES and more subjective and objective sleep problems.