Risk of bone tumors in children and residential proximity to industrial and urban areas: New findings from a case-control study.

Few epidemiologic studies have explored risk factors for bone tumors in children, and the role of environmental factors needs to be analyzed. Our objective was to ascertain the association between residential proximity to industrial plants and urban areas and risk of bone tumors in children, taking into account industrial groups and toxic pollutants released. A population-based case-control study of childhood bone cancer in Spain was carried out, covering 114 incident cases obtained from the Spanish Registry of Childhood Tumors (between 1996 and 2011), and 684 controls individually matched by sex, year of birth, and autonomous region of residence. Distances from the subject's residences to the 1271 industries and the 30 urban areas (towns) with ≥75,000 inhabitants located in the study area were computed. Unconditional logistic regression models were fitted to estimate odds ratios (ORs) and 95% confidence intervals (95%CIs) for categories of distance (from 1km to 3km) to industrial and urban areas, with adjustment for matching variables and sociodemographic indicators. Excess risk (OR; 95%CI) of bone tumors in children was detected for children close to industrial facilities as a whole (2.33; 1.17-4.63 at 3km) - particularly surface treatment of metals (OR=2.50; 95%CI=1.13-5.56 at 2km), production and processing of metals (OR=3.30; 95%CI=1.41-7.77 at 2.5km), urban waste-water treatment plants (OR=4.41; 95%CI=1.62-11.98 at 2km), hazardous waste (OR=4.63; 95%CI=1.37-15.61 at 2km), disposal or recycling of animal waste (OR=4.73; 95%CI=1.40-15.97 at 2km), cement and lime (OR=3.89; 95%CI=1.19-12.77 at 2.5km), and combustion installations (OR=3.85; 95%CI=1.39-10.66 at 3km)-, and urban areas (4.43; 1.80-10.92). These findings support the need for more detailed exposure assessment of certain toxics released by these facilities.