Secular trends of sleep-wake patterns in Hong Kong preschoolers

Influence of lifestyle and family environment factors on mental health problems in Hong Kong preschoolers

BACKGROUND AND AIMS

Existing studies that simultaneously consider the effects of lifestyle and family environment factors on mental health problems (MHPs), particularly in preschoolers, are limited. This study aims to explore lifestyle and family environment factors associated with MHPs, externalising problems (EPs) and internalising problems (IPs) in preschoolers.

METHODS

This territory-wide, school-based study conducted from 2020 to 2022 involved 1926 preschoolers. MHPs, EPs, and IPs and factors such as sleep duration, sleep latency, entertainment screen time, educational screen time, parent-child recreation and learning activities were assessed. Linear and logistic regression analyses were used to explore the relationships between these factors and MHPs, EPs, and IPs.

RESULTS

The average sleep duration was 9.94 h per day, average screen time of 2.53 h per day, and 42.6 % experienced sleep latency exceeding 20 min per day among preschoolers (mean age: 4.39 years, 49.1 % female). Adjusted analyses showed that decreased parent-child recreation activities, prolonged sleep latency and excessive entertainment screen time were associated with increased MHPs, EPs, and IPs (β: 0.05 to 0.20, all p < 0.05). Weekend sleep duration of <10 h per day, sleep latency of >20 min per day, and educational screen time of >30 min per day were identified as risk factors for MHPs, EPs, and IPs, with an adjusted odds ratio ranging from 1.32 to 2.32 (all p < 0.05).

CONCLUSIONS

Preschoolers' lifestyle and family environment factors are associated with MHPs, EPs, and IPs respectively. Ensuring adequate sleep duration, avoiding sleep latency exceeding 20 min per day, reducing entertainment screen time, limiting educational screen time to 30 min per day, and increasing parent-child interactions may help to minimise mental health problems.

Actigraphy-assessed sleep duration and quality and executive function in a sample of typically developing preschoolers

Sleep is essential for cognitive development and brain maturation during early childhood. Studies focused on preschool populations using objective measures of sleep are still scarce. The objective of this study was to examine the associations between objective measures of sleep duration and quality with executive functioning in a 133 non-clinical sample of Spanish participants (Mage = 60.33 months, SD = 9.04; ages 41-77 months; 51.1% girls). Sleep was assessed for five weeknights using actigraphy; Shape School task was applied to assess inhibition and cognitive flexibility; and Word Span task was used to assess working memory. The results revealed that relation between sleep and executive functioning was significant for inhibition and working memory. Preschoolers with higher sleep efficiency showed better results in executive functioning tasks after controlling for the effect of age. Additionally, age and sleep duration and quality variables were predictive of inhibition, working memory, and cognitive flexibility. These results suggest that the different dimensions of sleep could play an important role in the development of executive functions during preschool age. Therefore, improving sleep could lead to an improvement in children's executive functioning in both clinical and educational contexts.

Autobiographical memory specificity and objective sleep quality: the role of preschool stress

Autobiographical memory specificity and sleep undergo significant changes across the preschool years. This study sought to examine the association between actigraphy-measured sleep quality and autobiographical memory specificity in preschoolers. Additionally, we analyzed the mediating role of sleep in the relationship between stress and autobiographical memory. The sample comprised 67 participants (Mage = 60.39 months, SD = 9.25). To measure the study variables, we used the Autobiographical Memory Test-Preschoolers, wGT3X-BT actigraphs, an ad hoc healthy sleep questionnaire, and the Children's Daily Stress Inventory. Total sleep duration and sleep efficiency were found to be positively related to autobiographical specificity. Furthermore, the participants adhering to recommendations on sleep showed higher levels of specificity compared to those whose sleep patterns were inappropriate. The negative impact of stress on specific memory increased when the indirect effects of poorer sleep duration and efficiency were included, suggesting a moderated mediation effect, where sleep moderates the relationship between stress and specific memory. These findings could have significant implications for preschoolers' cognitive development and mental health, highlighting the role of sleep and stress in influencing memory and emotional well-being.

Secular trends in sleep and circadian problems among adolescents in Hong Kong: From 2011-2012 to 2017-2019

OBJECTIVE

The study aimed to investigate secular trends in sleep and circadian problems in Hong Kong Chinese adolescents.

METHODS

This study analyzed cross-sectional data from two large-scale school-based sleep surveys conducted in 2011-2012 and 2017-2019. Sleep and circadian problems, including sleep-wake pattern, insomnia, chronotype, social jetlag, daytime sleepiness, and other sleep-related factors, were compared between two survey years.

RESULTS

A total of 8082 adolescents (5639 students in 2011-2012 [Mean age: 14.4 years, 50.9% boys] and 2443 students in 2017-2019 [Mean age: 14.7 years, 54.0% boys]) were included in this 7-year study. The average time in bed of Hong Kong adolescents decreased from 8.38 hours to 8.08 hours from 2011-2012 to 2017-2019. There was a 0.28-hour delay in weekday bedtime, 0.54-hour advance in weekend wake-up time, and a 0.36-hour decline in average time in bed, resulting in increased trends of sleep loss (Time in bed <8h: OR = 2.06, 95%CI: 1.44-2.93, p < 0.01; Time in bed <7h: OR = 2.73, 95%CI: 1.92-3.89, p < 0.01), daytime sleepiness (OR = 1.70, 95%CI: 1.34-2.16, p < 0.01), and evening chronotype (OR = 1.26, 95%CI: 1.08-1.48, p < 0.01). The increased trend in insomnia disorder, however, was insignificant when covariates were adjusted.

CONCLUSION

A secular trend of reduced time in bed, delay in weekday bedtime, advance in weekend wake-up time, increase in evening chronotype and daytime sleepiness from 2011-2012 to 2017-2019 were observed. There is a timely need for systematic intervention to promote sleep health in adolescents.