Study Design and Participants' Profile in the Sub-Cohort Study in the Japan Environment and Children's Study (JECS).

Makiko Sekiyama,Takehiro Michikawa,Shoji F Nakayama,Yu Taniguchi,Junzo Yonemoto,Hiroshi Nitta,Shin Yamazaki,Toshihiro Kawamoto,Masaji Ono,Kenji Tamura,Michihiro Kamijima,Tomohiko Isobe,Yayoi Kobayashi,Eiko Suda,Miyuki Iwai-Shimada

doi:10.2188/jea.je20200448

Abstract

BackgroundThe Japan Environment and Children’s Study (JECS) is a nationwide birth cohort study investigating environmental effects on children’s health and development. A Sub-Cohort Study has begun, conducting extended exposure and outcome measurements by targeting a subgroup randomly selected from the JECS Main Study. We report the Sub-Cohort Study methodology and participants’ baseline profiles.MethodsOf 100,148 children in the JECS Main Study, children born after April 1, 2013 who met eligibility criteria ([1] all questionnaire and medical record data from children and their mothers collected from the first trimester to 6 months of age, [2] biospecimens [except umbilical cord blood] from children and their mothers collected at first to second/third trimester and delivery) were randomly selected for each Regional Centre at regular intervals. Face-to-face assessment of neuropsychiatric development, body measurement, paediatrician’s examination, blood/urine collection for clinical testing and chemical analysis, and home visits (ambient and indoor air measurement and dust collection) are conducted. Participants are followed up at 1.5 and 3 years old for home visits, and 2, 4, 6, and 8 years old for developmental/medical examination. The details of protocols after age 10 are under discussion.ResultsOf 10,302 selected children, 5,017 participated. The profiles of the participating mothers, fathers and children did not substantially differ between the Main Study and Sub-Cohort Study.ConclusionThe JECS Sub-Cohort Study offers a platform for investigating associations between environmental exposure and outcomes.

Highlights

The Japan Environment and Children’s Study (JECS) is a nationwide birth cohort study designed to examine the effects of various environmental factors on children’s health and development.[1,2,3,4] The main part of JECS (Main Study) aims to recruit 100,000 mother–child dyads, and to collect data from all participants
The study is designed to assess the effect of environmental factors, including exposure to chemical substances, on the proportion of reproduction=pregnancy complications, congenital anomalies, developmental disorders and immune= metabolic system dysfunction
A Sub-Cohort Study was established to perform these extended exposure and outcome measurements for a subgroup randomly selected from the Main Study

Summary

Introduction

The Japan Environment and Children’s Study (JECS) is a nationwide birth cohort study designed to examine the effects of various environmental factors on children’s health and development.[1,2,3,4] The main part of JECS (Main Study) aims to recruit 100,000 mother–child dyads, and to collect data from all participants. For some exposure and outcome measurements, home visits and person-to-person examination are required Such measurements include indoor air quality, house dust analysis, neurodevelopmental tests and paediatric examination. A Sub-Cohort Study was established to perform these extended exposure and outcome measurements for a subgroup randomly selected from the Main Study. A Sub-Cohort Study has begun, conducting extended exposure and outcome measurements by targeting a subgroup randomly selected from the JECS Main Study. We report the Sub-Cohort Study methodology and participants’ baseline profiles

Methods

Results

Conclusion