Influence of sleep-onset time on the development of 18-month-old infants: Japan Children's cohort study

Akiko Iemura; Mizue Iwasaki; Noriko Yamakawa; Kiyotaka Tomiwa; Yoko Anji; Yoichi Sakakihara; Tatsuyuki Kakuma; Shinichiro Nagamitsu; Toyojiro Matsuishi

doi:10.1016/j.braindev.2015.10.003

Influence of sleep-onset time on the development of 18-month-old infants: Japan Children's cohort study

Brain Dev. 2016 Apr;38(4):364-72. doi: 10.1016/j.braindev.2015.10.003. Epub 2015 Oct 23.

Authors

Akiko Iemura¹, Mizue Iwasaki¹, Noriko Yamakawa², Kiyotaka Tomiwa³, Yoko Anji⁴, Yoichi Sakakihara⁴, Tatsuyuki Kakuma⁵, Shinichiro Nagamitsu⁶, Toyojiro Matsuishi⁷

Affiliations

¹ Japan Children's Study Group (JCS), Research Institute of Science and Technology for Society, Japan Science and Technology Agency, Tokyo, Japan; Department of Pediatrics and Child Health, Kurume University School of Medicine, Fukuoka, Japan.
² Japan Children's Study Group (JCS), Research Institute of Science and Technology for Society, Japan Science and Technology Agency, Tokyo, Japan; Clinical Research Institute, Mie-chuo Medical Center, National Hospital Organization, Mie, Japan.
³ Japan Children's Study Group (JCS), Research Institute of Science and Technology for Society, Japan Science and Technology Agency, Tokyo, Japan; Graduate School of Medicine, Kyoto University, Kyoto, Japan.
⁴ Japan Children's Study Group (JCS), Research Institute of Science and Technology for Society, Japan Science and Technology Agency, Tokyo, Japan; Ochanomizu University, Tokyo, Japan.
⁵ Centre for Bio-Statistics, Kurume University School of Medicine, Fukuoka, Japan.
⁶ Department of Pediatrics and Child Health, Kurume University School of Medicine, Fukuoka, Japan.
⁷ Japan Children's Study Group (JCS), Research Institute of Science and Technology for Society, Japan Science and Technology Agency, Tokyo, Japan; Department of Pediatrics and Child Health, Kurume University School of Medicine, Fukuoka, Japan. Electronic address: toyojiro@st-mary-med.or.jp.

PMID: 26602742
DOI: 10.1016/j.braindev.2015.10.003

Abstract

Objective: We report here the influence of sleep patterns on the development of infants in Japan. A total of 479 infants were registered in two different Japanese cities. Direct neurological observations were performed by licensed pediatric neurologists.

Method: We designed a prospective cohort study and identified the sleep factors of children showing atypical development. The Kinder Infant Developmental Scale (KIDS) was used to evaluate the infant developmental quotient (DQ); we also applied a neurobehavioral screening battery. Neurobehavioral observations in 18-month-old infants were designed to check all developmental categories within the three areas of motor function, language, and social function. Based on the observations, each infant was classified as having "atypical development" or "typical development".

Result: We found that later sleep onset time (>22:00 h), and longer naps during the day each had significant positive correlations with atypical development patterns in 18-month-old infants. For each hour the infant sleep-onset time extended past 22:00 h, the infants showed worse neurodevelopmental outcomes, at an odds ratio increase of 2.944.

Conclusion: Although our results may be confounded by sleep problems resulting from pre-existing developmental disabilities, we can safely conclude that appropriate sleeping habits are important for healthy development in 18-month-old infants.

Keywords: Cohort study; Sleeping habits; Social development.

MeSH terms

Child Development*
Developmental Disabilities / physiopathology*
Female
Humans
Infant
Japan
Male
Neuropsychological Tests
Prospective Studies
Sleep*