Proximity to chipboard factories and adverse health risks: the Viadana study

Introduction Wood industry is the industrial sector with the main environmental impact in the Viadana area. Main pollutants produced during the woodworking process are wood dusts and fine dust, formaldehyde, nitrogen dioxide and carbon monoxide. The health effects of proximity to wood industries are not known, particularly in the pediatric population. Aims The aim of this thesis was to evaluate whether living in an industrial wood district is a health hazard for children. More precisely, we wanted to test if the prevalence of the irritation of the eyes, nose and throat, respiratory symptoms, and the use of health services varied with the distance of the children's homes (or schools) from wood industries. We also studied the association between vicinity to chipboard industries and hospital admissions for respiratory causes in children, and the prevalence and severity of respiratory symptoms. We finally explored the potential sensitivity of our results to the choice of the proxy of exposure used in the study, based on the proximity to the wood factories. Materials and Methods The Viadana study is a cross-sectional survey investigating the pediatric population of the health district of Viadana (Mantua, northern Italy), where several wood manufacturing industries are located. All children aged 3-14 attending school in the district were administered a standardized parental questionnaire to determine the prevalence of respiratory and irritative symptoms. 3,854 questionnaires were collected. The minimum distance (km) from the children's home/school to each factory was used as the proxy of exposure. For each subject, hospital discharge records for respiratory reasons were obtained from the local Health unit of Mantua (Italy) for the period 1st January 2002 to 13st December 2005. Results Children who live within 2 km from chipboard industries had a greater prevalence of respiratory symptoms (OR=1.33, 95%CI: 1.11, 1.60), cough/phlegm (OR=1.43, 95%CI: 1.08, 1.88), nose/throat/mouth (OR=1.47, 95%CI: 1.23, 1.75), eye (OR=1.24, 95%CI: 1.04, 1.48) irritation symptoms, school-days lost (OR=1.24, 95%CI: 1.04, 1.48), and emergency (OR=2.14, 95%CI: 1.47, 3.11) and hospital (OR=2.21, 95%CI: 1.17, 4.18) admissions. There was an inverse dose-response relationship between the adverse health outcomes considered and the distance from the plants. Hospitalization rates for respiratory reasons increased with the proximity to the wood factories: it was 502.9 (95%CI: 347.2, 728.3) for subjects who live far from any wood factory, 748.3 (95%CI: 519.9, 1076.7) for those living within 2 km from a small wood factory and 1130.9 (95%CI: 885.1, 1444.8) for subjects who live close to a chipboard factory. Conclusions Results of the Viadana study suggest that emissions from chipboard industries might have a serious impact on children's health status and should therefore be reduced and closely monitored.