Longitudinal Cohort Studies on Child Health in South East Asia

Abstract

Children are more vulnerable to adverse environmental exposures than adults and are often exposed to higher doses of toxicants. The consequences of exposure depend on the developmental stage during which the exposures occur. While many organ systems are mature at or soon after birth the respiratory, immune, and central nervous system have prolonged periods of postnatal maturation making them vulnerable to environmental exposures occurring after birth. While cross-sectional studies can provide information about associates between exposures and health outcomes, the optimal method for determining the adverse effects of environmental exposures is to follow a group of children from before or at birth, carefully measuring exposures and outcomes over time. Longitudinal cohort studies present a particular set of challenges that need to be overcome. Such studies are expensive to undertake and require dedicated personnel. Many studies are too small to identify links between exposures and less common outcomes. Here, the use of harmonized protocols can be beneficial in allowing data to be combined from a number of studies, thus increasing the power to detect small effects. This presentation will focus on a general approach to conducting longitudinal studies on respiratory health and neurodevelopment. Examples from existing cohorts and studies in the planning phase will be used.