Title: Cohort study and environmental exposure, recent progress in Japan
Authors: Ayano Takeuchi - Keio University (Japan) [presenting]
Abstract: Two topics will be considered. One is to assess the effect of environmental chemical exposure on fetuses or development of children using birth cohort data. Another is to assess the health effect of air pollution on cardiovascular and respiratory diseases. Ministry of the Environment, Japan have launched birth cohort study targeting 100,000 pregnant from 2011 to evaluate health effect of environmental chemical on fetuses or children. In exposure assessment, there is a problem of detection limits (DLs) and quantitation limits (QLs) of exposure substances. We can convert these problems to incomplete data problem or left-censored data problem. DLs and QLs may differ depending not only on substances, but also measurement batch, time and equipment within same substance. The other problem is that exposure and outcomes are affecting each other over time. Evaluating the relationship between baseline risks and outcomes used in conventional epidemiological studies is not enough. Statistical models dealing with birth cohort data have not yet been established. We may use causal inference approach such as drawing DAGs or separating direct and indirect effects using conditional models etc. Health effects of air pollution are often evaluated by merging existing cohort data or existing official statistics with air pollution data. Time series data analysis, case cross over analysis or generalized additive models are used when evaluating short term health effects.