Rationale and study design of the Japan environment and children’s study (JECS)

TLDR

Global concern exists over environmental hazards threatening children, underscoring the need for large‑scale, long‑term birth cohort studies to inform sound environmental management. The Japan Environment and Children’s Study (JECS) aims to elucidate how environmental factors influence children’s health and development by recruiting about 100,000 expectant mothers nationwide over three years. JECS follows children until age 13, assessing exposures through chemical analyses of bio‑specimens, household measurements, computational simulations of monitoring data, and questionnaires, while also evaluating genetic, socioeconomic, and lifestyle covariates to identify substances affecting fetal and early childhood development. JECS prioritizes outcomes such as reproductive complications, congenital anomalies, neuropsychiatric, immune, and metabolic disorders, with results intended to improve risk assessment and environmental management for future generations.

Abstract

There is global concern over significant threats from a wide variety of environmental hazards to which children face. Large-scale and long-term birth cohort studies are needed for better environmental management based on sound science. The primary objective of the Japan Environment and Children's Study (JECS), a nation-wide birth cohort study that started its recruitment in January 2011, is to elucidate environmental factors that affect children's health and development.Approximately 100,000 expecting mothers who live in designated study areas will be recruited over a 3-year period from January 2011. Participating children will be followed until they reach 13 years of age. Exposure to environmental factors will be assessed by chemical analyses of bio-specimens (blood, cord blood, urine, breast milk, and hair), household environment measurements, and computational simulations using monitoring data (e.g. ambient air quality monitoring) as well as questionnaires. JECS' priority outcomes include reproduction/pregnancy complications, congenital anomalies, neuropsychiatric disorders, immune system disorders, and metabolic/endocrine system disorders. Genetic factors, socioeconomic status, and lifestyle factors will also be examined as covariates and potential confounders. To maximize representativeness, we adopted provider-mediated community-based recruitment.Through JECS, chemical substances to which children are exposed during the fetal stage or early childhood will be identified. The JECS results will be translated to better risk assessment and management to provide healthy environment for next generations.