European birth cohorts offer insights on environmental factors affecting human development and health

European countries, particularly the UK, have a long history of conducting birth cohort studies. Now a new birth cohort, the UK's Life Study, has ambitious plans to enroll tens of thousands of participants and a hope that it will succeed where its counterpart in the USA, the National Children's Study (NCS) has failed. 1 The NCS was dissolved in December 2014 by the Director of the National Institutes of Health (NIH) amid concerns over the study's feasibility and costs. 2,3 Although the NIH remains committed to the over-arching goals of the NCS, 2 to 'find alternative ways to study child development and environmental influences on health', 4 it is unclear when and how this is likely to happen. However, ready options to address the goals of NCS are available among the European birth cohorts 5,6 and are likely to have international relevance beyond Europe. Authorized by the Children's Health Act of 2000, the NCS was a prospective birth cohort study developed to evaluate the effects of environmental exposures on child health and human development. 2,7 The vision for the NCS was to enrol a probability sample of 100 000 children and examine a broad range of environmental and biological factors. The study was meant to be a 'complete assessment of the physical, chemical, biological and psychosocial environmental influences on children's well-being' 2 and to address socioeconomic and racial/ethnic disparities in environmental exposures and health outcomes. 2 Several Vanguard Centres were launched to test the feasibility, acceptability and costs of running the main study. But after years of struggling to get off the ground and numerous criticisms, a working group set up to review the fate of the study concluded that although the goals of the NCS were meritorious, the study was not feasible in its current form. 2 The longitudinal birth cohort design was one of the strengths of the NCS when a panel of experts was convened to evaluate the study and recommend its future. 2 In its initial design, the NCS planned on enrolling women before conception, to account for antenatal exposures. However, given the large costs, slow pace and inefficiencies involved with this recruitment strategy, the traditional recruitment at antenatal visits seemed appropriate and justified 7 and was ultimately adapted. 8 Collectively, European birth cohorts offer an excellent opportunity to investigate the types of questions that the NCS was intended to address. These cohorts bring together several …