Environmental chemicals and their effects on children based on the first birth cohort studies in Japan

Abstract

Since the publication of Theo Colborn et al.'s Our Stolen Future in 1996, global interest in the impact of chemical substances on endocrine disrupting action has escalated. In Japan, “The Hokkaido Study on Environment and Children's Health: Malformation, Development, and Allergy” was launched in 2001. It was a model of Japan Environment and Children's Study of the Ministry of the Environment that started 10 years later. In a Hokkaido large-scale cohort, we obtained 20,926 mothers' consent at the organogenesis stage, with the cooperation of 37 obstetrics clinics in Hokkaido. We follow up children's health outcomes, including birth size, neonatal hormone levels, neurobehavioral development, asthma, allergies, and infectious diseases. In a small-scale Sapporo cohort, we observed the detailed neuropsychiatric development of children with the consent of 514 mothers in the late pregnancy. We examined how prenatal exposure to low concentrations of environmental chemicals affect the prenatal and postnatal development of children. The maternal exposures to persistent organic pollutants, such as PCB/Dioxins, polyfluorinated alkyl substances, and organochlorine pesticides, affected children's birth size, thyroid function, and sex hormone levels, and their postnatal neurodevelopment, infection, and allergy, among others. Effects of short half - life substances, such as phthalates and bisphenol A were also investigated. Gene-environment interactions were found in smoking, caffeine, folic acid, and PCB/Dioxin. Epigenome modification was also investigated. In 2011, three principle investigators of Japan, Korea, and Taiwan cohorts established the Birth Cohort Consortium in Asia, comprising 29 birth cohorts of 15 countries. Many collaborating studies will be expected from the consortium in the near future.