Exposure to Environmental Chemicals and Children’s Health: Findings from the Hokkaido Study

Rachel Carson’s “Silent Spring” (1962) raised global awareness of the persistence of pesticides and their ecological impacts. Forty years later, the Hokkaido Study on Environment and Children’s Health was initiated in 2002 as a large-scale, birth cohort study. Its primary aim is to investigate the health effects of environmental chemical exposure and to provide scientific evidence for environmental policy. Between 2002 and 2012, approximately 20,000 pregnant women from Hokkaido were recruited for the study. Their children, aged 13–23 years, were followed up. Maternal health and lifestyle data and blood samples were collected during the pregnancy. Medical records and umbilical cord blood samples were collected at the time of birth. Follow-up questionnaires were administered to children of various ages to collect information on child development, allergies, infections, and other health indicators. Face-to-face surveys conducted at school and during pubertal age selected a subset of participants living in the Sapporo area to collect detailed data, including cognitive and respiratory function tests, pubertal development evaluations, and biological sampling. Internal exposure to environmental chemicals was assessed using chemical analyses of blood and urine samples collected from mothers and children. This study provides important insights into the health effects of prenatal and postnatal chemical exposure. This presentation highlights the key findings of the Hokkaido Study, including exposure trends in the general Japanese population, associated health outcomes, and future research directions.