Determinants of sleep patterns in healthy Japanese 5-year-old children.

BACKGROUND: Early childhood is an important period for the development of sleep patterns; studies of sleep patterns in young preschool children may help elucidate the mechanism of associated mental/physical conditions and later sleep problems. AIM AND METHODS: The aim of this study was to investigate intrinsic and extrinsic independent variables associated with sleep patterns in preschool children using actigraphy. Forty-eight 5-year-old children from two types of nurseries, which accommodate children with (Type A) or without (Type B) in-home caregivers, were invited to undergo a 7-day actigraphic sleep study.
RESULTS: Compared with weekdays, both sleep onset time and sleep end time were later on weekends (28 and 17 min later in average, respectively). On weekdays, cultural lessons were associated with a later sleep onset time (22 min later); female gender, sports lessons and fixed bathing times were related with an earlier sleep end time (17, 21 and 17 min earlier, respectively); sports lessons were also associated with higher sleep efficiency (3.7% higher). During weekends, unfixed bedtimes and daytime naps were related with a later sleep onset time (73 and 54 min later, respectively); male gender, Type A nursery and daytime naps were associated with a later sleep end time (33, 37 and 34 min later, respectively); sports lessons were associated with higher sleep efficiency (3.6% higher).
CONCLUSIONS: Our current findings suggested that both intrinsic and extrinsic factors, such as gender, child care, lifestyle and after-nursery lessons, influence the establishment of sleep patterns in young preschool children. Further investigation of these independent variables may help establish a strategy for predicting and preventing sleep disorders later in life.