Findings from the Birth Cohort Study on Allergy: Two prospective cohort studies, the T-Child and Japan Environment and Children's Study-

Abstract

Although the prevalence of allergic diseases is rapidly increasing, the full picture of the associated factors remains unclear. The birth cohort study, i.e., a prospective, rather than a retrospective, study of the general population close to the population, preventing bias, is considered the highest level of evidence for capturing disease changes over time and making causal inferences about exposures and outcomes. Two birth cohort studies are currently being conducted: The T-Child study, a single-center study at the National Center for Child Health and Development, and the Japan Environmental Children's Study (JECS), the first nationwide prospective cohort study in Japan. These studies revealed various findings: Actual conditions of allergic disease onset in the Japanese population, various related factors including maternal exposure, actual conditions of the allergic march beyond adolescence, and positions of pollen-food allergy syndrome (PFAS), which has recently been attracting attention, in the allergic march. Based on these reports, this paper, as much as possible, summarizes the actual situation and related factors of allergic march in Japanese children that have been clarified to date.