Conclusion
This study revealed that both >9 h of MSD and excessive
gestational BWG had great impact on the incidence of LBW and SGA, and 9
to <10 h of MSD decreased the risk of LBW and SGA in women
with appropriate gestational BWG. It is important for care providers to
provide the latest data for proper counseling regarding the association
between MSD and neonatal birth weight and suggest comprehensive
modifications in lifestyles of pregnant women, including sufficient MSD,
to prevent LBW and SGA. Furthermore, because JECS is a prospective
cohort study, future elucidation of long-term childhood outcomes on the
basis of MSD and neonatal birthweight would strengthen the conclusion of
this study.
Acknowledgements: The authors are grateful to all the
participants of the study and to the Ministry of the Environment, Japan.
Members of the JECS Group as of 2020 are: Michihiro Kamijima (principal
investigator, Nagoya City University, Nagoya, Japan), Shin Yamazaki
(National Institute for Environmental Studies, Tsukuba, Japan), Yukihiro
Ohya (National Center for Child Health and Development, Tokyo, Japan),
Reiko Kishi (Hokkaido University, Sapporo, Japan), Nobuo Yaegashi
(Tohoku University, Sendai, Japan), Koichi Hashimoto (Fukushima Medical
University, Fukushima, Japan), Chisato Mori (Chiba University, Chiba,
Japan), Shuichi Ito (Yokohama City University, Yokohama, Japan), Zentaro
Yamagata (University of Yamanashi, Chuo, Japan), Hidekuni Inadera
(University of Toyama, Toyama, Japan), Takeo Nakayama (Kyoto University,
Kyoto, Japan), Hiroyasu Iso (Osaka University, Suita, Japan), Masayuki
Shima (Hyogo College of Medicine, Nishinomiya, Japan), Youichi Kurozawa
(Tottori University, Yonago, Japan), Narufumi Suganuma (Kochi
University, Nankoku, Japan), Koichi Kusuhara (University of Occupational
and Environmental Health, Kitakyushu, Japan), and Takahiko Katoh
(Kumamoto University, Kumamoto, Japan).
Disclosure of interests: The authors report no conflicts of
interest.
Contribution to Authorship: T.M. conceptualized and designed
the study. T.M., H.K., T.F., S.Y., A.Y., S.M., K.H., H.N., and K.F.
contributed to the study design. K.S., A.S., and Y.O. collected the
data. T.M. analyzed the data and wrote the manuscript. M.H., S.Y., K.H.,
K.S., A.S., Y.O., H.N., K.F., and the JECS group reviewed the manuscript
and provided critical advice. All authors approved the final manuscript.
Details of Ethical Approval: The JECS protocol was reviewed and
approved by the Ministry of the Environment Institutional Review Board
on Epidemiological Studies on March 23, 2010 (No.
15000141)22,23 and by the Ethics Committees of all
participating institutions. The JECS was conducted in accordance with
the principles of the Declaration of Helsinki and other national
regulations and guidelines. Written informed consent was obtained from
all participating women.
Funding: The Japan Environment and Children’s Study was funded
by the Ministry of the Environment, Japan. The findings and conclusions
of this article are solely the responsibility of the authors and do not
represent the official views of the Ministry of the Environment, Japan.