This study compared sleep habits and electronic media usage in community-dwelling children aged 18 months and 42 months, grouped according to their life patterns. Empirical research is lacking concerning the effects of exposure to electronic media devices and the influence of life patterns on electronic media usage for infants and toddlers. To our knowledge, this is the first study to compare sleep habits and media usage in relation to whether children attended kindergarten, nursery school, or stayed at home. Usage of the terms “kindergarten” and “nursery school” varies between countries. Kindergarten and nursery school are types of preschools that enroll children aged ≤ 5 years. In Japan, kindergartens are for children aged 3–5 years, and are considered to be more of an educational preparation for school, and are supervised by the Ministry of Education, Culture, Sports, Science, and Technology. In contrast, nursery schools are essentially for children aged 0–5 years whose caregivers work during the day, and these nurseries are under the jurisdiction of the Ministry of Health, Labour, and Welfare.
This study, conducted during health check-ups, identified that sleep habits of children both 18- and 42-month-old differed according to specific life patterns. Among the 18-month-old children, those who stayed at home had a longer sleep duration on weekends and woke up later than those attending nursery school. The 42-month-old children attending nursery school went to bed later and woke up earlier than those attending kindergarten or staying at home and had the longest daytime naps among the three groups.
In terms of naps, there were no significant differences in the number of days with naps and in the nap duration between 18-month-old children attending nursery school and those staying at home. In contrast, significantly different patterns were observed in the 42-month-old children attending nursery school who were found to nap on a greater number of days per week (5.6 days/week) and for a longer duration (94.8 min) than those in the other two groups. Fukuda et al. (2002) reported the sleeping patterns of Japanese kindergarten and nursery school children aged between 3 and 6 years and found that nursery school children went to bed later at night and their night-time sleep was shorter than that of children attending kindergarten. Moreover, the afternoon nap appeared to cause delayed sleep onset but was not a result of sleep deficiency, as shown through a comparison of the sleep duration on the previous night and the sleep onset time between the days with and without an afternoon nap . In our study, nap conditions significantly differed among the children in the 42M group attending kindergarten, attending nursery school, and staying at home. Nursery school children with obligatory naps had later bedtimes among the 42-month-olds. It may be worth considering whether children attending nursery schools should have such long nap times.
Our research showed that television, smartphones, and tablet devices were the most popular electronic media devices used by both 18- and 42-month-old children, of whom 77% in the 18M group and 84.5% in the 42M group watched television regardless of their life pattern. A smartphone was used by 22% of 18-month-old children and 46% of 42-month-old children. A tablet device was used by 10% of 18-month-old children and 19% of 42-month-old children. The use of mobile devices, including smartphones and tablet devices, by young children has increased dramatically since the Kaiser Foundation began research into the use of technology for parents of 0- to 8-year-olds . In 2011, 52% of children aged 0–8 years were able to access mobile devices; however, by 2013 this had increased to 75% . Recent trends indicate that smart devices are becoming increasingly popular among children. A touch-based multi-modal interface smart device provides an easy-to-use platform for young children, especially when compared with using an electronic mouse, which requires fine motor and keyboard techniques .
There were no significant differences in electronic media usage between 18-month-old children attending and not attending nursery school, except for portable game use time. However, a greater number of the 42-month-old children attending kindergarten used portable games and home video games compared with those attending nursery schools or those staying at home. Children attending kindergarten arrive at kindergarten later and leave for home earlier than nursery school children. Consequently, kindergarten children would have more free time at home than those attending nursery schools. Moreover, it is possible that 42-month-old children attending kindergarten have more time available to be influenced and/or taught how to work electronic media devices by their elder siblings or by neighborhood children. However, it is unclear why more of the children remaining at home did not use electronic games. Our results indicated that more attention should be paid to children attending kindergartens, especially in relation to acquiring appropriate screen time habits as habits developed in childhood could have a significant effect throughout their lifetime.
Many studies have shown that excessive screen time for young children is associated with language delay, attention problems, obesity, aggressive behavior, and sleep problems [13, 23, 24, 25]. Moreover, screen time habits formed in early childhood have been shown to predict negative psychological and health outcomes later in life [26, 27, 28]. One recent longitudinal study demonstrated that parental monitoring of children’s media influenced their sleep, school performance, and prosocial and aggressive behaviors, and that limiting the amount of media use and its content was a powerful protective factor for children between the third and fifth grades . Our results indicating the use of screen media games in early childhood may imply a need for early intervention.
One strength of this study was that attention was paid to the children’s lifestyles rather than those of their caregivers. Moreover, sleep habits and media usage were compared in relation to whether children attended kindergarten, nursery school, or stayed at home. This study had some limitations that should be considered for an appropriate interpretation of the results. First, the children’s sleep habits were evaluated using questionnaires answered by the parents or caregivers, rather than through using objective sleep measurements such as actigraphy. Second, data concerning parents’ socioeconomic status and behaviors were unavailable; therefore, this information could not be related to the children’s sleep patterns. Third, because of the relatively small sample size, the present study could not conduct comprehensive analyses concerning associations between children’s sleep habits, media usage, and life patterns.