Study design
In this study, data from the Japan Environmental Children’s Study
(JECS), a government-funded birth cohort study that started in January
2011, were used. This survey investigated the effect of several
environmental factors on children’s health.19Eligibility requirements of JECS participants (mothers) were as follows:
(1) living in the study area at the time of application and were
expected to live in Japan in the near future; (2) expected delivery date
was between August 1, 2011, and mid-2014; and (3) could participate
without difficulty (i.e. they could answer the self-management
questionnaire). Written informed consent was obtained from all
participating women.
The JECS protocol was reviewed and approved by the Ministry of the
Environment’s Institutional Review Board on Epidemiological Studies and
by the Ethics Committees of all participating institutions. The JECS was
conducted in accordance with the Helsinki Declaration and other
nationally valid regulations and guidelines.