The potential health risks of exposure to environmental chemicals - Global implications for future generations

In 2001, we launched the Hokkaido Study, the first prospective birth cohort study in Japan. We are currently tracking the effects of environmental chemicals, using a life course approach. The study examines life circumstances after birth, and the longest follow-up to date is 20 years of age. We have measured prenatal exposure to dioxins, organochlorine pesticides, per- and polyfluoroalkyl substances, plasticizers such as di(2-ethylhexyl) phthalate, and bisphenol A. Our findings have mostly revealed that increased exposure to these environmental chemicals is linked to increased risk of lower birth size, effects on thyroid and steroid hormones, adipokine levels, as well as disruption of neurodevelopment, including causing asthma and respiratory symptoms. However, it should be noted that our findings also include protective or null findings, which may be due to low chemical concentrations or differences in prenatal or postnatal exposure. We would like to emphasize the importance of long-term continuation of the cohort, effective utilization of the data, and application of the results to environmental and health policies.