title: Agricultural crop exposure and risk of childhood cancer: new findings from a case-control study in Spain.
abstract: Childhood cancer is the main cause of disease-related death in children in Spain. Although little is known about the etiology, environmental factors are potential explanations for a fraction of the cases. Previous studies have shown pesticides to be associated with childhood cancer. The difficulty of collecting personal environmental exposure data is an important limitation; this lack of information about pesticides motivates the development of new methods to subrogate this exposure. We developed a crop exposure index based on geographic information to study the relationship between exposure to different types of crops and risk of childhood tumors.
  
  
  
  We conducted a population-based case-control study of childhood cancer covering 3350 cases and 20,365 controls in two Spanish regions. We used CORINE Land Cover to obtain data about agricultural land use. We created a 1 km buffer around every child and calculated the percentage of crop surface within the buffer (Global Crop Index) for total crops and for individual types of crops. We fitted mixed multiple unconditional logistic regression models by diagnostic group.
  
  
  
  We found excess of risk among children living in the proximity of crops. For total crops our results showed excesses of risk for almost all diagnostic groups and increasing risk with increasing crop index value. Analyses by region and individual type of crop also showed excess of risk.
  
  
  
  The results suggest that living in the proximity of cultivated land could be a risk factor for several types of cancer in children.
authors.affiliation: Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain. dgomez@externos.isciii.es.|National Center for Epidemiology, Carlos III Institute of Health, Monforte de Lemos 5, Pb. 12, 28029, Madrid, Spain. dgomez@externos.isciii.es.
authors.forename: Diana
authors.initials: D
authors.lastname: Gómez-Barroso
authors.affiliation: Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain.|Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: García-Pérez
authors.affiliation: Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain.|Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain.
authors.forename: Gonzalo
authors.initials: G
authors.lastname: López-Abente
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.|Universitat Pompeu Fabra (UPF), Barcelona, Spain.
authors.forename: Ibon
authors.initials: I
authors.lastname: Tamayo-Uria
authors.affiliation: Rare Disease Research Institute (IIER), Carlos III Institute of Health, Madrid, Spain.|Consortium for Biomedical Research in Rare Diseases (CIBERER), Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Morales-Piga
authors.affiliation: Spanish Registry of Childhood Tumors (RETI-SEHOP), University of Valencia, Valencia, Spain.
authors.forename: Elena
authors.initials: E
authors.lastname: Pardo Romaguera
authors.affiliation: Consortium for Biomedical Research in Epidemiology and Public Health (CIBERESP), Madrid, Spain.|Cancer and Environmental Epidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain.
authors.forename: Rebeca
authors.initials: R
authors.lastname: Ramis
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D018556:Crops, Agricultural; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D040362:Geographic Information Systems; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D009369:Neoplasms / Q000453:epidemiology*; D010575:Pesticides; D012307:Risk Factors; D013030:Spain
chemical_list: D010575:Pesticides
keywords: Cases/control; Childhood cancer; Crops; GIS; Spatial epidemiology