and birth cohorts have been set up across Europe (e.g., Golding et al. 2001; Hofman et al. 2004; Magnus et al. 2006; Olsen et al. 2001; Raynor 2008; Richiardi et al. 2007), in North America, and elsewhere (Brown et al. 2007; Herbstman et al. 2010; Marks et al. 2010; Richter et al. 2011), and more are being planned (Hirschfeld et al. 2011). Many cohort studies include assessments of environmen- tal pollutant exposure, but not all have large expertise in this area. Although it is clear that individual cohorts are able to make, and have made, important contributions to understand- ing environmental causes of childhood dis- ease and ill health, it is becoming increasingly clear that their full potential can be realized only with collaboration across large regions (Kogevinas et al. 2004). The European Union (EU) has funded the Environmental Health Risks in European Birth Cohorts (ENRIECO) project to coor- dinate birth cohort research in Europe in the area of environmental contaminant expo- sures (ENRIECO 2009). ENRIECO recog- nized that a comprehensive overview of birth cohorts and their data was needed as a first step toward improved collaboration, future project planning, and effective use of existing data. Currently, no inventory of environmen- tal exposure data exists. The aim of this review is to provide an overview of European birth cohorts with data on environmental contami- nant exposures and health outcomes. Methods Definition and identification of cohorts. Birth cohort studies were included in the project if they a) collected data on at least one environ- mental contaminant exposure topic (air pollu- tion, water contamination, pesticides, metals, persistent organic pollutants, other chemical pollutants, noise, radiations, and allergens and biological organisms); b) started enrollment of mothers into the cohort during pregnancy or at birth; c) included in their protocol at least one follow-up point after birth with direct con- tact with mothers and children; d) included at least 200 mother–child pairs (a low sample size limit was chosen so small studies with relevant exposure data or based in less well-covered regions were not excluded); and e) were based in a European country. Collection of data on an environmental exposure topic included data collected through questionnaires, environmen- tal sampling, spatial maps and models, per- sonal monitoring, biomarker measurements, or a combination of these methods. The mere availability of residential location (addresses and geocodes) was not sufficient for inclusion. All cohorts fitting the criteria were considered regardless of when they started, when they con- ducted their most recent follow-up, whether data had been published, or whether recruit- ment of subjects was ongoing. Cohorts were identified through a variety of sources: www.birthcohorts.net (Birthcohorts.net 2010), a searchable Web site that contains basic protocol information for a number of birth cohorts; European projects using birth cohort data; and personal contacts. Publications and Web sites of identified cohorts were checked to see whether the cohort appeared to match the criteria of the inventory. All cohorts identified as potentially eligible between 1 March 2009 (start of the project) and 31 December 2010 were approached. Inventory questionnaire. An inventory questionnaire was designed to collect detailed information from the cohorts on biological sample collection, assessment of environmental exposures, assessment of child health outcomes of interest, and basic information on collection of other variables. The full questionnaire can be found in Supplemental Material, Annex 1 (http://dx.doi.org/10.1289/ehp.1103823). The questionnaire was divided into four sections: • Basic protocol description: protocol descrip- tion, basic data, and biological sample col- lection scheme. • Exposure assessment: air pollution (outdoor and indoor), water contamination, allergens and biological organisms, metals, pesticides, radiations (ionizing, ultraviolet, and non- ionizing), tobacco smoke (active and pas- sive), noise, persistent organic pollutants, Faroes ArcRisk-Norway MoBa HUMIS INUENDO BAMSE Leicester ALSPAC PÉLAGIE GenerationXXI INMA-new INMA-old BiB DNBC ABCD GenerKaOtiAonLAR DARC PIAMA FLEHS I PARIS EDEN Duisburg MAS LISAplus GINIplus Co.N.ER NINFEA GASPII European birth cohorts occupation (maternal and paternal), and other chemical compounds. Each section asked for the exposure assessment methods used, numbers of subjects assessed, and time point of assessment. • Health outcome assessment: reproduction and birth outcomes, neurodevelopment, aller- gies and asthma, cancer, child growth, and metabolic syndrome indicators such as blood pressure, cholesterol, triglycerides, insulin, or glucose. Each section asked which outcomes were assessed, by which methods (if relevant), how many subjects were assessed, and the time point of assessment. • Other information: mainly yes/no questions on collection of genotype data, residential history, time–activity patterns, sociodemo- graphic variables, breast-feeding, diet, physical exercise, medical history, and anthropometry. The questionnaire was sent to principal investigators of each identified cohort, who were asked to distribute specific sections to the appropriate researchers and data managers within their cohort. The completed question- naire was checked and, if necessary, the cohort study teams were contacted again to correct errors and complete information. Cohorts that did not reply to the first e-mail were reminded repeatedly by e-mail or phone. Cohorts were invited to two workshops during the project, in which the aims and objectives were presented. No. of children at birth < 1,000 1,000–5,000 5,000–20,000 100,000 KANC INUENDO REPRO_PL Czech Kraków PCB cohort INUENDO LUKAS RHEA Figure 1. European birth cohort studies collaborating in ENRIECO. Environmental Health Perspectives • volume 120 | number 1 | January 2012 31