Vrijheid et al. environmental contaminant exposures, espe- cohorts, but usually for a small number of sub- this an optimal time to work toward a high cially those measuring exposure biomark- jects in each cohort and with considerable vari- level of data comparability. ers, usually cannot cover large numbers of ation in the type and timing of the biological Birth cohorts are most suitable to examine subjects. Smaller, specialized cohorts, often samples. Studies combining data from differ- child health outcomes that are common or located in high-exposure areas, have made ent cohorts have been conducted for few such can be measured on a continuous scale. Rare very important contributions in this regard. pollutants so far; examples are the 7-cohort outcomes and pathologies such as extremely Passive smoking, maternal (and paternal, lead meta-analysis (Lanphear et al. 2005) and preterm birth, childhood cancers, congeni- less often) occupation, air pollution, and aller- a recent meta-analysis of 12 European cohorts tal anomalies, and autism can be studied gen exposures have been assessed by many evaluating PCB and DDE exposure and fetal only in the very large cohorts or by combin- birth cohorts. Efforts to combine data analyses growth (Govarts et al. 2011). Exposure areas ing cohorts, as is being done, for example, in on these topics are already ongoing within that are less well covered in the cohorts include the International Childhood Cancer Cohort international projects such as European Study noise, ionizing and nonionizing radiations, Consortium (Brown et al. 2007). All cohorts of Cohorts for Air Pollution Effects (ESCAPE) and chemical exposures such as brominated collected information on fetal growth and (2009), Global Allergy and Asthma European and fluorinated compounds, phthalates, and gestational length and on childhood anthro- Network (GA2LEN) (2009), and International phenols (including bisphenol A). These are pometric measures; combined studies of Collaboration on Air Pollution and Pregnancy areas of emerging concern for child health these outcomes appear feasible. A number of Outcomes (ICAPPO) (Woodruff et al. 2010). and high on international research agendas cohorts specialize in the early causes of asthma Biomarker data on some metals (lead and [e.g., the World Health Organization (WHO) and allergies, and combined studies of these mercury) and some persistent organic pollut- Research Agenda for Radiofrequency Fields] outcomes are underway (Keil et al. 2006a, ants [polychlorinated biphenyls (PCBs) and (WHO 2010). Although actual measurements 2006b). Neurodevelopment is a wide area that dichlorodiphenyldichloroethylene (DDE)] are are scarce, future assessments of these expo- encompasses many cognitive and behavioral also available in a relatively large number of sures are planned in many cohorts, making outcomes and includes even more assessment Table 3. Assessment of environmental exposures (prenatal or postnatal) in European birth cohorts participating in ENRIECO.a Air Air Allergens and Persistent Other pollution pollution Water biological organic chemical Passive Cohort outdoor indoor contamination organisms Metalsb Pesticidesc pollutants exposuresd Radiations smokinge Noise Occupation ABCD X X X g X X ALSPAC X X X X X g X X X X ArcRisk-Norway X X X g X X BAMSE X X X X X BiB X X X Co.N.ER X g X X X X X Czech X X X DARC X X X X X DNBC X g X X X X X X X Duisburg X X X g X X X X X X EDEN X X X g X X X X X ELFE X g X g X g X g X g X g X g X g X g X g X g Faroes X X g X X g X X FLEHS I X X X X X X X X GASPII X X X X X Generation R X X X X g X X X X Generation XXI X X X GINIplus X X X X HUMISf X X X X X g X X X X X X INMA old X X X X X g X X X X X X X INMA new X X X X X X X X X X X X INUENDO X g X g X g X g X X KANC X X X X g X KOALA X X X X g X X X Kraków X X X X X X X X X Leicester X X X X X LISAplus X X X X X g LUKAS X X X X X X g X X MAS X X X X X MoBa X g X X X X g X X g X X X X X NINFEA X g X g X g X g X g X g X g X g X g PARIS X X X X X X PCB cohort X X X X X g X X PELAGIE X X X X X X X X PIAMA X X X X REPRO_PL X g X X X X X X RHEA X X X X X X X g X g X X X X See Table 1 for full names and locations of cohorts. aDetails of each assessment (method, time period, number of subjects) are available at www.birthcohortsenrieco.net (ENRIECO 2011). bBiomonitoring data only, not questionnaires. cOrganochlorine pesticides are included under persistent organic pollutants. dPhthalates and phenols (including bisphenol A). ePassive smoking exposure of the mother during preg- nancy or of the child postnatally. fData on occupation and passive smoking are available through overlap with MoBa in approximately 800 participants. gMeasurements are planned or ongoing but not completed. 34 120 | number 1 | January 2012 • Environmental Health Perspectives ovlume