Short or Irregular Sleep Duration in Early Childhood Increases Risk of Injury for Primary School-Age Children: A Nationwide Longitudinal Birth Cohort in Japan

Abstract

The aim of this study was to investigate the longitudinal relationship between shorter or irregular sleep duration (SD) in early childhood and increased risk of injury at primary school age using data from a nationwide survey in Japan. We categorized SD into seven groups: 6 h, 7 h, 8 h, 9 hrs, 10 or 11 h, >12 h, and irregular, based on questionnaire responses collected at 5.5 years old. The relationship between SD and incidence of injury at 5.5–nine years of age is shown. In addition, we completed a stratified analysis on children with or without problematic behavior at eight years old. We included 32,044 children, of which 6369 were classified as having an injury and 25,675 as not having an injury. Logistic regression model showed that shorter or irregular SD categories were associated with an increased adjusted odds ratio (aOR) for injuries (6 h: aOR 1.40, 95% confidence interval (CI) 1.19–1.66, 7 h: aOR 1.10, 95% CI, 0.98–1.23, 8 h: aOR 1.13, 95% CI, 1.02–1.26, irregular: aOR 1.26, 95% CI 1.10–1.43). The same tendency was observed with shorter or irregular SD in subgroups with or without behavioral problems. Shorter or irregular sleep habits during early childhood are associated with injury during primary school age.

The effect of sleep disorders, school jet lag, and anxiety in students 8–10 years of age on traumatic dental injuries

“…52 Upon entering the school phase, children's habits change; they sleep less and suffer more accidental injuries due to the fact that they perform many routine activities alone. 22 Moreover, sleep disorders lead to a lack of concentration during the performance of these activities, 22 increasing the likelihood of the occurrence of TDI.…”

“…The findings confirmed the hypothesis, as the presence of sleep disorders was associated with a greater occurrence of TDI in children 8–10 years of age. It is possible that short or irregular sleep in early childhood increases the risk of accidental injuries, such as falls, during the school phase, 21,22 predisposing this group to TDI. These findings are in agreement with data reported in another study conducted in Brazil involving the same age group 7 …”

“…School jet lag occurs when there is a mismatch between the biological clock and school hours, resulting in sleep deprivation 15 . These clinical signs can contribute to the occurrence of accidental injuries 20–22 . However, there is a gap in the literature with regards to the study on the association between school jet lag and TDI.…”

“…15 These clinical signs can contribute to the occurrence of accidental injuries. [20][21][22] However, there is a gap in the literature with regards to the study on the association between school jet lag and TDI.…”

Asia–Pacific consensus statement on integrated 24-hour activity guidelines for the early years

“… 25 Sleep deprivation is an important issue in this region, with only an estimated 9% of Japanese 5-year-olds achieving the recommended amount of sleep daily. 26 …”