Association Between Sleep Duration and Intelligence Quotient in 6-Year-Old Children

Kyung-Shin Lee, Johanna Inhyang Kim, Yoon-Jung Choi, Jinwoo Cho, Youn-Hee Lim, Bung-Nyun Kim, Choong Ho Shin, Young Ah Lee, Yun-Chul Hong

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

BACKGROUND: Sufficient sleep during childhood is important for cognitive functions such as learning and successful school performance. This study aimed to investigate the effects of sleep duration on the intelligence quotient (IQ) of 6-year-old children and aimed to analyze whether these effects differed by sex.

METHODS: The IQ of 538 6-year-old Korean participants from the cohort study, "The Environment and Development of Children," was measured during follow-up using the Korean Educational Developmental Institute's Wechsler Intelligence Scale for Children. The total, verbal, and performance IQ scores were evaluated. The relationship between sleep duration and IQ scores after adjusting for maternal age, maternal educational level, maternal occupation, maternal IQ, exposure to secondhand smoking, gestational age, and monthly age and birth season was also assessed.

RESULTS: Longer sleep duration was significantly associated with improved verbal IQ measures (β 0.55; p value 0.030). After stratifying participants by sex, a significant association was observed between sleep duration and total, verbal, and performance IQ scores in boys (total IQ 2.49, p value 0.012; verbal IQ 0.75, p value: 0.037; performance IQ 0.73, p value 0.048), but not in girls.

CONCLUSIONS: The results indicated that only boys show a significant association between IQ scores and sleep duration. These findings support the hypothesis that sleep duration is associated with IQ, in a sex dependent manner. Future studies are needed for a thorough evaluation of the connection between sleep duration and health outcome in young children.

Original languageEnglish
JournalInternational Journal of Behavioral Medicine
Volume29
Pages (from-to)57–68
Number of pages12
ISSN1070-5503
DOIs
Publication statusPublished - 2022

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