LAUSR

F rederica Perera has stocked a dozen freezers with an unusual biological bounty over the past two decades. Inside are vials of umbilical-cord blood, urine and placentas from more than 700 pregnant women and their children from the Washing-ton Heights, Harlem and South Bronx neighbourhoods of New York City. This biobank has proved invaluable in her efforts to understand how urban environments influence children's health from birth through childhood. Now, Perera's team is gearing up for another challenge: developing a tool that can test her bank of umbilical-cord blood samples for common pollutants and use the results to predict later impacts on neurodevelopment and obesity. The scientists are also joining a major US government programme that seeks to understand how environmental, behavioural and social factors affect children's health. Known as the Environmental Influences on Child Health Outcomes (ECHO) programme, the effort will support dozens of longitudinal cohort studies across the United States. Researchers working on the project will meet on 15–16 February in Arlington, Virginia, to make decisions key to its success: how to collaborate, and how to combine and compare the individual data sets. The ECHO project emerged from the ashes of the controversial National Children's Study (NCS), a programme run by the US National Institutes of Health (NIH) that aimed to track 100,000 children from before birth to age 21. The NIH cancelled that study in 2014, after spending more than a decade and US$1.2 billion trying to get it off the ground. ECHO organizers say that their project will be different. By using cohorts that are already under way, they hope to side-step some of the problems that plagued the NCS, which had trouble recruiting participants, defining its hypotheses and sticking to its budget. Marrying up existing cohort studies will enable the scientists to study large numbers of children more cheaply than if they created one large cohort from scratch. Doing so will also let them examine rarer health outcomes and differences between subpopulations. But the approach brings its own problems. " The purpose of the national meeting is to try to combine the cohorts, " says Douglas Ruden, director of epigenomics at Wayne State University's Institute of Environmental Health Sciences in Detroit, Michigan, and a member of the ECHO steering committee who is helping to lead a participating cohort. " They all have different goals and study designs, and somehow they have to merge them into …