A systematic review of the association between sleep health and stress biomarkers in children

Are nocturnal awakenings at age 1 predictive of sleep duration and efficiency at age 6: Results from two birth cohorts

Objective

To investigate the association of nighttime awakenings at 12 months with the duration and efficiency of nighttime sleep at 6 years of age.

Methods

Data from two population-based prospective studies (The Pelotas 2004 and The Pelotas 2015 Birth Cohorts) were used. Information on nighttime awakenings was provided by mothers during the 12-month follow-up interview. Infants who awakened >3 times after sleep onset at 12 months were considered frequent wakeners. Sleep duration and sleep efficiency were obtained by actigraphy at the 6-year follow-up. Children wore the device at the wrist of the non-dominant arm continuously for 3-7 days, including at least one weekend day. Unadjusted and adjusted beta coefficients were obtained by linear regression for each cohort separately.

Results

2500 children from the 2004 and 2793 from the 2015 cohort had full information on nighttime awakenings at 12 months and actigraphy at 6 years and were analyzed. Prevalence of frequent wakeners was 6.3 % and 5.9 % in the 2004 and 2015 cohort, respectively. Mean bedtime and wake-up time at 6 years were, respectively, 23:23 and 08:41 h in the 2004 cohort, and 00:10 and 09:00 h int the 2015 cohort. Nighttime sleep lasted on average 7.54 and 7.24 h respectively in the 2004 and the 2015 cohort, and the sleep efficiency was 81.1 and 82.5 % respectively. In adjusted analyses, no associations were found between awakening at 12 months and sleep duration or sleep efficiency at 6 years of age.

Conclusion

In both cohorts sleep duration and efficiency were below the recommendation for school-age children (respectively 9-11 h and 85 %). There was no relationship between the number of nighttime awakenings at 12 months and sleep duration or efficiency at 6 years.

Association of lifestyle with sleep health in general population in China: a cross-sectional study

The concept of a healthy lifestyle is receiving increasing attention. This study sought to identify an optimal healthy lifestyle profile associated with sleep health in general population of China. An online cross-sectional survey was conducted from June to July 2022. Six healthy lifestyle factors were assessed: healthy diet, regular physical exercise, never smoking, never drinking alcohol, low sedentary behavior, and normal weight. Participants were categorized into the healthy lifestyle (5-6 factors), average (3-4 factors), and unhealthy lifestyle groups (0-2 factors). The study's primary outcome was sleep health, which included sleep quality, duration, pattern, and the presence of any sleep disorder or disturbance, including insomnia, excessive daytime sleepiness, obstructive apnea syndrome, and narcolepsy. Multivariable logistic regression analysis was applied to explore lifestyles associated with the selected sleep health outcomes. 41,061 individuals were included, forming 18.8% healthy, 63.8% average, and 17.4% unhealthy lifestyle groups. After adjusting for covariates, participants with healthy lifestyle were associated with a higher likelihood of good sleep quality (OR = 1.56, 95% CI = 1.46-1.68), normal sleep duration (OR = 1.60, 95% CI = 1.49-1.72), healthy sleep pattern (OR = 2.15, 95% CI = 2.00-2.31), and lower risks of insomnia (OR = 0.66, 95% CI = 0.61-0.71), excessive daytime sleepiness (OR = 0.66, 95% CI = 0.60-0.73), and obstructive apnea syndrome (OR = 0.40, 95% CI = 0.37-0.43), but not narcolepsy (OR = 0.92, 95% CI = 0.83-1.03), compared to those with unhealthy lifestyle. This large cross-sectional study is the first to our knowledge to quantify the associations of a healthy lifestyle with specific aspects of sleep health. The findings offer support for efforts to improve sleep health by modulating lifestyle.

Adverse Childhood Experiences and Accelerometer-Measured Physical Activity and Sleep in Preadolescents

OBJECTIVE

To assess the relationship between adverse childhood experiences (ACEs) and objective measures of physical activity and sleep.

METHODS

Data from the baseline and 2-year follow-up of the Adolescent Brain and Cognitive Development study were analyzed (n = 6227 for physical activity; n = 4151 for sleep). ACEs were assessed by parent report at baseline (mean age 9.9 years) with 3 levels: none, exposure to 1 ACE, and exposure to 2 or more ACEs. Objective measures of physical activity and sleep were assessed with an accelerometer at 2-year follow-up (mean age 11.9 years). Multivariate linear regression analyses were used to examine the relationship between ACEs and physical activity as well as sleep, adjusting for family income and sex.

RESULTS

Compared to children with no ACEs, children with ACEs had fewer daily steps: 1 ACE (β = -323 (95% CI: -508 to -138), P < .001) and 2 or more ACEs (β = -417 (95% CI: -624 to -209), P < .001). ACEs were also associated with shorter sleep duration (minutes), although only for participants with 2 or more ACEs (1 ACE: β = -2.2 (-5.3 to 0.8), P = .16; 2 or more ACEs: β = -6.2 (95% CI: -9.6 to -2.7), P < .001). Rapid eye movement (REM) sleep specifically was reduced in participants with ACEs (1 ACE (β = -1.4 (-2.7 to -0.01), P = .05) and 2 or more ACEs (β = -2.3 (-3.8 to -0.8), P = .003).

CONCLUSIONS

There is a dose-response relationship between ACEs and reduced daily steps, total sleep duration, and REM sleep in preadolescents.

Salivary α-amylase as a marker of sleep disorders: A theoretical review

Sleep disorders are commonplace in our modern societies. Specialized hospital departments are generally overloaded, and sleep assessment is an expensive process in terms of equipment, human resources, and time. Biomarkers would usefully complement current measures in the screening and follow-up of sleep disorders and their daytime repercussions. Among salivary markers, a growing body of literature suggests that salivary α-amylase (sAA) may be a cross-species marker of sleep debt. However, there is no consensus as to the direction of variation in sAA with sleep disorders. Herein, after describing the mechanisms of sAA secretion and its relationship with stress, studies assessing the relationship between sAA and sleep parameters are reviewed. Finally, the influence of confounding factors is discussed, along with methodological considerations, to better understand the fluctuations in sAA and facilitate future studies in the field.

How emotions impact sleep: A quantitative review of experiments

Although sleep and emotional processes are recognized as mutually dependent, the causal impact of emotions on sleep has been comparatively neglected. To appraise evidence for the causal influence of emotions on sleep, a meta-analysis of the existing experimental literature evaluated the strength, form, and context of experimental effects of emotion inductions on sleep parameters (k = 31). Quality of experiments was evaluated, and theoretically-relevant features were extracted and examined as moderating factors of observed effects (i.e., sleep parameter, design, sleep context, types of emotion inductions and emotions). Random-effect models were used to aggregate effects for each sleep parameter, while-mixed effect models examined moderators. There was a significant impact of emotion inductions on delayed sleep onset latency (D = 3.36 min, 95%CI [1.78, 4.94], g = 0.53), but not other parameters. There was little evidence of publication bias regarding sleep-onset latency effect, the studies overall were heterogeneous, sometimes of limited methodological quality, and could only detect moderate-to-large impacts. The findings supported the hypothesis that negative emotions delayed sleep onset, but evidence regarding other sleep parameters was inconclusive. The results call for more targeted investigation to disambiguate distinct features of emotions and their import for sleep.

Family Rules and Routines During the Early Phases of Pediatric Cancer Treatment: Associations With Child Emotional and Behavioral Health

OBJECTIVE

Consistent family rules and routines promote positive adaptation to stress and may be protective to child emotional and behavioral functioning. Few studies have quantified family engagement in these behaviors during pediatric cancer treatment or examined associations with child emotional and behavioral health.

METHODS

In this cross-sectional observational study, 86 primary caregivers of youth ages 2-14 years (M = 7.9) with an initial diagnosis of cancer within 16 weeks reported on their frequency of engagement in family rules and routines (e.g., sleep, schoolwork, and meal routines) before their child's cancer diagnosis and their current frequency of engagement in the same routines. Caregivers also reported demographics, psychosocial distress, and child emotional and behavioral health outcomes. Analyses examined demographic and psychosocial factors associated with engagement in rules and routines during cancer treatment, and associations with child emotional and behavioral health.

RESULTS

Families reported a lower frequency of engagement in rules and routines during cancer treatment, compared to before treatment (mean difference 0.8 SDs [95% confidence interval 0.7-1.1 SDs]). Caregiver factors associated with lower engagement in rules and routines during treatment included being married, having lower educational attainment, and higher levels of psychosocial distress. Families who engaged in higher levels of rules and routines during treatment reported fewer child externalizing and behavioral challenges. There was limited evidence of association between family rules and routines and child internalizing outcomes.

CONCLUSIONS

Results found that engaging in family rules and routines during cancer treatment was associated with fewer child behavioral challenges during treatment. Future directions include longitudinal examinations of family rules, routines, and child emotional/behavioral outcomes to examine directional impact over time.

Social Capital and Sleep Outcomes Across Childhood in United States Families

OBJECTIVE

To examine whether aspects of social capital, or benefits received from social relationships, are associated with regular bedtime and sleep duration across childhood in US families with lower income.

METHODS

Cross-sectional study using the 2018-19 National Survey of Children's Health in participants with incomes <400% federal poverty level. Separately for early childhood (0-5 years), school-age (6-12 years), and adolescence (13-17 years), we used weighted logistic regression to examine associations between social capital (measured by family social cohesion, parent social support, child social support) and sleep (measured by regular bedtime, sleep duration, adequate sleep per American of Academy of Sleep guidelines). Path analysis tested whether regular bedtime mediated associations between social capital and sleep duration.

RESULTS

In our sample (N = 35,438), 84.9% had a regular bedtime, 60.2% had adequate sleep. Family social cohesion was associated with sleep duration and adequate sleep (infancy: adjusted odds ratio [aOR] 2.18 [95% confidence interval [CI], 1.32, 3.60]; school age: aOR 2.03 [95% CI, 1.57, 2.63]; adolescence: aOR 2.44 [95% CI, 1.94, 3.09]). In toddlerhood, parent social support was associated with adequate sleep (aOR 1.44 [95% CI, 1.06, 1.96]). In adolescence, child social support was associated with regular bedtime (aOR 1.70 [95% CI, 1.25, 2.32]. Across childhood, associations between family social cohesion and sleep duration were partially mediated by regular bedtime.

CONCLUSIONS

Family social cohesion was associated with adequate sleep across childhood, this was partially mediated by regular bedtime. Associations between social support and sleep outcomes varied by development stage. Future work should consider how supportive relationships may influence child sleep outcomes.

Disparities in greenspace associated with sleep duration among adolescent children in Southern California

More than half of adolescent children do not get the recommended 8 hours of sleep necessary for optimal growth and development. In adults, several studies have evaluated effects of urban stressors including lack of greenspace, air pollution, noise, nighttime light, and psychosocial stress on sleep duration. Little is known about these effects in adolescents, however, it is known that these exposures vary by socioeconomic status (SES). We evaluated the association between several environmental exposures and sleep in adolescent children in Southern California.

Methods

In 2010, a total of 1476 Southern California Children's Health Study (CHS) participants in grades 9 and 10 (mean age, 13.4 years; SD, 0.6) completed a questionnaire including topics on sleep and psychosocial stress. Exposures to greenspace, artificial light at night (ALAN), nighttime noise, and air pollution were estimated at each child's residential address, and SES was characterized by maternal education. Odds ratios and 95% confidence intervals (95% CIs) for sleep outcomes were estimated by environmental exposure, adjusting for age, sex, race/ethnicity, home secondhand smoke, and SES.

Results

An interquartile range (IQR) increase in greenspace decreased the odds of not sleeping at least 8 hours (odds ratio [OR], 0.86 [95% CI, 0.71, 1.05]). This association was significantly protective in low SES participants (OR, 0.77 [95% CI, 0.60, 0.98]) but not for those with high SES (OR, 1.16 [95%CI, 0.80, 1.70]), interaction P = 0.03. Stress mediated 18.4% of the association among low SES participants.

Conclusions

Residing in urban neighborhoods of greater greenness was associated with improved sleep duration among children of low SES but not higher SES. These findings support the importance of widely reported disparities in exposure and access to greenspace in socioeconomically disadvantaged populations.

Bullying victimization and internalizing and externalizing problems in school-aged children: The mediating role of sleep disturbance and the moderating role of parental attachment

BACKGROUND

Studies have shown that bullying victimization may be related to internalizing and externalizing problems; however, the mechanism underlying this relationship remains unknown. This study explored the mediating role of sleep disturbance and the moderating role of parental attachment.

METHODS

A total of 1543 Chinese primary school students (M age = 8.92 years, SD1.7 years; range, 6-12) completed bullying victimization, sleep disturbance, and parental attachment measures, and provided information on their parents' occupations. The parents or guardians (n = 1995) also completed ratings on their children's internalizing and externalizing problems.

RESULTS

It was found that bullying victimization directly affected internalizing and externalizing problems and also influenced sleep disturbance. Regardless of the parent's socioeconomic status, parental attachment was found to moderate the relationship between bullying victimization and internalizing problems.

CONCLUSIONS

These findings contribute to understanding the partial mediating mechanism of sleep disturbance in the association between bullying victimization and internalizing and externalizing problems. The protective role of parental attachment proved central to preventing internalizing problems in bullied children. Intervention programs that enhance parental attachment and improve sleep quality could assist in mitigating the impact of bullying victimization on internalizing or externalizing problems.

Environmental Noise Exposure and Sleep Habits among Children in a Cohort from Northern Spain

Environmental noise is considered the second most serious environmental risk factor in Europe. However, little evidence exists regarding its impact on health and sleep in children, and the results are inconclusive. In this study, we aim to analyse the effect of environmental noise exposure on 11-year-old children's sleep habits. Data were collected from 377 participants in the INMA-Gipuzkoa (INfancia y Medio Ambiente) cohort project using both parent-reported and actigraphic sleep measures. The results revealed that 60% of children have a day-evening-night environmental noise exposure (L_den) of above 55 dB, which is defined as a "high noise level". No differences in noise exposure were observed between different socioeconomic groups. However, no effect of environmental noise was found on sleep variables. The paper highlights the importance of studying how environmental noise may affect children's sleep.

Self-reported changes in sleep patterns and behavior in children and adolescents during COVID-19

The COVID-19 pandemic and lockdowns worldwide forced children and adolescents to change and adapt their lives to an unprecedented situation. Using an online survey, we investigated whether they showed changes in sleep quality and other related factors due to this event. Between February 21st, 2021 and April 19th, 2021, a total of 2,290 Austrian children and adolescents (6-18 years) reported their sleep habits and quality of sleep as well as physical activity, daylight exposure and usage of media devices during and, retrospectively, before the pandemic. Results showed an overall delay of sleep and wake times. Almost twice as many respondents reported having sleeping problems during the pandemic as compared to before, with insomnia, nightmares and daytime sleepiness being the most prevalent problems. Furthermore, sleeping problems and poor quality of sleep correlated positively with COVID-19 related anxiety. Lastly, results showed a change from regular to irregular bedtimes during COVID-19, higher napping rates, a strong to very strong decrease in physical activity and daylight exposure, as well as a high to very high increase in media consumption. We conclude that the increase in sleeping problems in children and adolescent during COVID-19 is concerning. Thus, health promoting measures and programs should be implemented and enforced.

Association Between Adverse Childhood Experiences and Diet, Exercise, and Sleep in Pre-adolescents

OBJECTIVE

To understand the relationship between adverse childhood experiences (ACEs) and diet, sleep, and exercise in pre-adolescents.

METHODS

Baseline and 1-year follow-up data from the adolescent brain and cognitive development (ABCD) study were analyzed (age 10-11, n = 11,875). ACEs were measured by parent report at baseline. Three levels of ACEs were created: none, exposure to one ACE, and exposure to two or more ACEs. Health-promoting behaviors were assessed at 1 year. Diet quality was measured from parent report; sleep problems were measured by parent report, with higher scores indicating worse sleep; and amount of exercise was measured by youth report. Linear regression analyses were used to assess the relationship between ACEs and each health-promoting behavior, adjusting for family income and sex.

RESULTS

Compared to children with no adversity, ACEs were associated with worse diet - one ACE (β = -0.30 [95% CI, -0.49 to -0.12], P = .002) and 2 or more ACEs (β = -0.56 [-0.78 to -0.34, P < .001). Similarly, ACEs were associated with poor sleep - one ACE (β = 1.51 [1.00-2.03], P < .001) and 2 or more ACEs (β = 2.96 [2.38-3.53], P < .001). Finally, amount of exercise was not different in children with ACEs - 2 or more ACEs (β = -0.24, 95% CI, -0.51 to 0.04, P = .08).

CONCLUSIONS

ACEs in pre-adolescents show a dose-response relationship with unhealthy diet and sleep disruption. These findings suggest potential behaviors to target to mitigate the negative impact of childhood adversity on adult health.

Associations between cumulative risk, childhood sleep duration, and body mass index across childhood

Background

Although associations between cumulative risk, sleep, and overweight/obesity have been demonstrated, few studies have examined relationships between these constructs longitudinally across childhood. This study investigated how cumulative risk and sleep duration are related to current and later child overweight/obesity in families across the United States sampled for high sociodemographic risk.

Methods

We conducted secondary analyses on 3690 families with recorded child height and weight within the Fragile Families and Child Well-Being Study. A cumulative risk composite (using nine variables indicating household/environmental, family, and sociodemographic risk) was calculated for each participant from ages 3-9 years. Path analyses were used to investigate associations between cumulative risk, parent-reported child sleep duration, and z-scored child body mass index (BMI) percentile at ages 3 through 9.

Results

Higher cumulative risk experienced at age 5 was associated with shorter sleep duration at year 9, b = − 0.35, p = .01, 95% CI [− 0.57, − 0.11]. At 5 years, longer sleep duration was associated with lower BMI, b = − 0.03, p = .03, 95% CI [− 0.06, − 0.01]. Higher cumulative risk at 9 years, b = − 0.34, p = .02, 95% CI [− 0.57, − 0.10], was concurrently associated with shorter sleep duration. Findings additionally differed by child sex, such that only male children showed an association between sleep duration and BMI.

Conclusions

Results partially supported hypothesized associations between child sleep duration, cumulative risk, and BMI emerging across childhood within a large, primarily low socioeconomic status sample. Findings suggest that reducing cumulative risk for families experiencing low income may support longer child sleep duration. Additionally, child sleep duration and BMI are concurrently related in early childhood for male children.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03587-6.

Editorial: Environmental conditions for growing healthy children

The deleterious developmental effects of exposure to early adversity have been well documented in the scientific literature. The finding that poverty in early childhood is among the most robust predictors of a range of poor developmental outcomes has been well known for decades. More recently, evidence that early experiences of poverty and related forms of adversity negatively impact the function and structure of the developing brain have also emerged. Retrospective studies linking poor physical health outcomes to adverse childhood experiences (ACES) highlighted the more global nature of these risk factors to wellbeing and follow-up prospective studies have since confirmed these findings (Brown et al., 2009). Alternatively, it has become increasingly clear that early experiences of stimulation, nurturance, and caregiver support promote positive development outcomes with emerging evidence for tangible impacts on neurodevelopment in humans (Luby et al., 2021). However, the scientific and public health community has yet to synthesize these related bodies of data and develop a plan of action related to their over-reaching and global importance to protecting and promoting childhood health and development more generally despite numerous calls to do just that (Farah, 2018; Luby et al., 2020).

Sleep Deficiency in Young Children

There is growing public health concern about the high prevalence of sleep deficiency in early childhood and the associated risk for sleep-associated poor health outcomes, including metabolic, cardiovascular, and mental health. The recent shift to conceptualize sleep health as a multidimensional construct, influenced by socioecological factors, highlights the potential role of sleep in health disparities. Understanding the development of sleep health and the emergence of sleep disorders in early life is a current priority in pediatric sleep research. Future behavioral sleep interventions should consider the multiple socioecological influences on children's sleep health and be tested using inclusive sampling methods.

Associations between Childhood Maltreatment and Behavioral Sleep Disturbances Across the Lifespan: A Systematic Review

Childhood maltreatment has a range of long-term developmental and health consequences. Emerging research suggests that sleep disturbances may be a key behavioral health risk factor implicated in the relationship between maltreatment and poor health across the lifespan. This systematic review examined the association between maltreatment and behavioral sleep disturbances in childhood and adulthood. Studies were identified through PsycINFO, PubMed, and alternative search strategies such as Google Scholar and reference list checks, with an end date of July 2021. Quantitative, peer-reviewed articles examining behavioral sleep outcomes and/or characteristics among maltreatment-exposed samples were included. We assessed the potential risk of bias by examining study design and sleep and maltreatment assessment methods. Across 73 studies included in this review, there was a robust association between childhood maltreatment and behavioral sleep disturbances. Findings suggest that linkages between maltreatment and sleep outcomes diverge with respect to maltreatment characteristics, type of behavioral sleep disturbance assessed, use of subjective versus objective measures, and study design. Given that behavioral sleep disturbances are modifiable, more research is needed that incorporates objective measures of sleep and longitudinal designs to identify specific points of intervention to mitigate the potential long-term impacts of childhood maltreatment on health across socio-demographically diverse populations.

Sufficient sleep duration in autistic children and the role of physical activity

LAY ABSTRACT

Higher levels of physical activity may be associated with improved sleep in children, but this relationship is still being determined, especially in autistic children. In this study, we used existing data from the 2018 National Survey of Children's Health. Caregivers of children 6-17 years old, including caregivers of autistic children, completed a questionnaire that included questions about physical activity (days active in the past week) and sleep duration. We then determined if children were obtaining the recommended hours of sleep for their age (i.e. sufficient sleep). We found that higher physical activity levels were associated with sufficient sleep duration, but this finding was weaker in autistic children. In particular, this association was not observed in autistic children with more severe autism spectrum disorder, female autistic children, and autistic children 6-12 years old. In conclusion, physical activity is a promising approach to help children obtain sufficient sleep duration. However, more personalized approaches to improving sleep may be needed for certain groups of autistic children.