Healthy sleep is essential for children’s and adolescents’ physical and mental well-being. As we know, the investigation of sleep problems for children and adolescents are relatively limited in China up to now. In the present study conducted in a large sample of elementary and junior high school students in Fujian Province, China, we explore whether sleep health (sleep duration, sleep disturbance, subjective sleep quality) was associated with behavioral, social and physical factors to provide some reference value for suggestions for their sleep health in the future.
We observed sex, age, types of school and region differences that suggest need for tailored sleep promotion recommendations for children and adolescents with different characteristics. Boys had a higher sleep health scores and had lower sleep quality than girls, which is in the line with that of previous studies[12,13]. The older the age in our study, the higher the sleep score, where a higher score means poorer sleep. Some biological factors such as reduced homeostatic sleep pressure and delayed circadian rhythms in conjunction, as well as early high school start times and psychological changes from childhood to adolescence, might account for the differences in sleep among children and adolescents[14,15]. Elementary and junior high school students living in urban areas had more adverse sleep than those living in rural areas. Urban students have more night activities compared to rural students because of social and economic developmental disparities, which might result in reduced sleep duration of urban students and have a negative impact on sleep. The types of school difference in children and adolescents is also indicated in this study. A 12-country study demonstrates that experiencing some or a lot of fast-paced and highly competitive school environment (in comparison to none or a little school pressure) was associated with a decrease of sleep duration of 4.56 min per day and an increase of sleep onset difficulties of 0.32 respectively. Based on this study as well as previous researches, we speculate that the difference may be due to students in key schools suffer from a high academic burden and test stress, placing them under a high level of psychological stress that may aggravate the sensitization of the sleep system and lead to heightened alertness, physiological arousal and difficulty falling asleep.
It is known lifestyles have an effect on sleep health. In the current study, unhealthy living and behavioral characteristics including Excessive daytime sleepiness, Unhealthy sleep habits, Eating before sleep, social media usage (Screen time per day during school, Frequency of using electronics 30 minutes before bedtime, Using electronic products in bedroom) and Sleep alone have caused negative influence on sleep health.
Our study result shows that activities related to electronic products or media exposure before bedtime increased the incidence of sleep problem in children and teenagers and found one in five adolescents or children were classed as very high users, the crowd of using social media before bedtime everyday. With the popularity of electronic products or media, the proportion of users who own mobile phones increased, which has caused a series of critical health problems[19,20,21]. Accumulating studies for the past 10 years suggested that students who had using electronic products or media habit before bedtime had made easily sleep health worse than others[12,22,23]. Consistent with these studies, Akçay D, et al. demonstrated that as the teenager in Konya High School spent more time on their social media, their sleep quality become progressively worse. The decrease of self-reported sleep duration among U.S. adolescents 2009-2015 correlated with new media screen time. More than 50% of adolescents in our study had electronic products or media such as computer, iPad, callphone or television in their bedroom. Continente X, et al. demonstrated that adolescents with media devices in their bedroom were more likely to be short sleepers. Through electronic products or media (computer, Internet, smartphone, et al) usage, teenagers often play games, watch movies, TV-series, or entertainment shows, chat online or other activities. These activities, a stimulus for brain stimulating neurons contributed to increasing the occurrence adverse sleep outcomes in students. Moreover, as long time use of screen at night, eyes of students are exposed to strong light, and its blue spectrum has a strong and specific effect on the retina. Light can not only prevent the secretion of melatonin to leading to circadian rhythm disorder, but also cause the desire of awakening to delaying sleep. Besides, some adolescents reported have difficulties disengaging from social media to sleep.
19.9% of the current sample had co-sleeper, which associate negatively with sleep health. Due to co-sleepers may do more activities, such as talking and playing before going to bed, or made sleeping environment noisy, sleep problems are prone to come out easily in students sharing bed or room, which makes it easier for students to fall into the unhealthy habit of sleep. Meanwhile, our results also shows unhealthy sleep habits such as getting up late in the morning, stay up late, and energetic exercise before bed, was related with sleep health. Furthermore, excessive daytime sleepiness are related significantly to sleep health. We suspect if a student is drowsy during the day, there will be fragmentation of night sleep and increased sleep pressure, which will affect night sleep. Our findings suggest that food intake preceding sleep have a negative impact on sleep health, consistent with previous studies[31,32]. A previous study showed snacking and drinking caffeinated beverages before going to bed were associated with significantly short sleep duration and poorer sleep quality (OR=1.49 and 1.83, respectively).
Relationship with families and peers also appeared to play a pivotal role in sleep health. Because home and school are the two places which students’ lives mainly involve in, students who received more social support from family and friends reported greater life satisfaction. According to previous research, for children and adolescents, higher psychosocial well-being was linked to longer nocturnal sleep duration and lower levels of sleep disturbances. In our study, students who are satisfied with their family life/classmates relationship sleep better. The hypothalamic-pituitary -adrenal axis was activated with the release of hormones affect sleep architecture due to endure stress which in childhood can emerge from various sources like problems with the family and peers.
In the current study, fluctuation of emotions an important factor for unhealthy sleep, which is consistent with previous studies[37,38]. Emotion and sleep are closely linked and many studies have shown that heightened emotional reactivities including strong positive and negative emotions are related to the maintenance of insomnia symptoms. According to previous studies, affective processes mediate the effect of cognitive and autonomic hyperarousal on sleep. Sleep problems are confirmed to be associated with decreased levels of vagal suppression, which is considered indices of emotion regulation. Additionally, higher levels of emotional intensity tied in with reduced sleep duration and increased nocturnal activity. However, the relationship between mood and sleep is complex and bidirectional because poor emotions can worsen sleep and vice versa, further research is needed.
To data, comparable data on sleep deprivation among children and adolescents in Fujian is limited, but our study adds relevant research evidence in this aspect. Furthermore, another strength in the current study is a Cross sectional study of relatively large sample size and comprehensive assessments on a series of sleep health variables, which make us research on the potential factors influencing sleep. However, several limitations should be noted. The first is that causality will be difficult to demonstrate in cross-sectional design, although there are multiple theories to support our findings. Second, the current research does not include factors such as family structure and socioeconomic status, school timetable and parents’ sleeping habits, which may be significantly related to sleep health of Chinese students. Moreover, as a result of graduation having heavy academic stress, the last-year students (grades 6, 9 and 12) were not included into investigate.