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Kato T, Yorifuii T, Yamakawa M, Inoue S

Bioeffects Seen

Authors not listed · 2018

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Children with delayed bedtimes at age 6 nearly double their risk of excessive mobile phone use by age 12.

Plain English Summary

Summary written for general audiences

Japanese researchers tracked 9,607 children from age 6 to 12, finding that kids who went to bed late at age 6 were nearly twice as likely to excessively use mobile phones, especially for texting, by age 12. The study also found increased risks for excessive TV viewing and video game use among the late-bedtime children.

Why This Matters

This longitudinal study reveals a concerning pattern: early sleep disruption predicts excessive device use years later. What makes this particularly relevant to EMF health is the timing - children who develop poor sleep habits early become heavy users of EMF-emitting devices during critical developmental years. The science demonstrates that sleep and EMF exposure create a vicious cycle: devices disrupt sleep through blue light and EMF exposure, while poor sleep habits drive increased device dependence. The reality is that parents face a compounding problem where early sleep issues snowball into years of intensive EMF exposure during adolescence, when brain development is most vulnerable.

Exposure Information

Specific exposure levels were not quantified in this study.

Cite This Study
Unknown (2018). Kato T, Yorifuii T, Yamakawa M, Inoue S.
Show BibTeX
@article{kato_t_yorifuii_t_yamakawa_m_inoue_s_ce4752,
  author = {Unknown},
  title = {Kato T, Yorifuii T, Yamakawa M, Inoue S},
  year = {2018},
  doi = {10.1111/apa.14255},
  
}
DOI: 10.1111/apa.14255PubMed: 29385278

Quick Questions About This Study

Yes, this study found children going to bed after 10 PM at age 6 had nearly double the risk of excessive mobile phone use, particularly texting, by age 12 compared to those sleeping before 9 PM.
Researchers followed 9,607 Japanese children for 6 years, from age 6 to 12, using data from the Japanese Longitudinal Survey of Newborns that began in 2001.
Yes, children with delayed bedtimes at age 6 showed increased risks for excessive use of mobile phones, television viewing, and video games by age 12, not just one type of device.
The study specifically found that delayed bedtimes at age 6 were most strongly associated with excessive weekend texting at age 12, suggesting recreational rather than school-related phone use.
While this studied Japanese children specifically, the biological relationship between sleep disruption and device dependency likely applies across cultures, though usage patterns may vary by country.