Assessment of lead exposure and associated risk factors in urban children in Silesia, Poland.
A program of childhood lead poisoning prevention was conducted in six cities of Silesia, the most industrialized region of Poland. We analyzed records of 11,877 children aged 24-84 months, tested between 1993 and 1998, to assess children's exposure to lead and associations of blood lead levels (BLL) with season of sampling, questionnaire data, and environmental levels of lead. Air lead concentrations and lead fallout, as measured in the ambient air monitoring system, were below current Polish air quality standards and gradually decreased. The geometric mean (GM) BLL was 6.3 microg/dL (range from 0.6 to 48 microg/dL), and >13% of children had BLL > or =10 microg/dL. Mean BLL declined from 6.8 microg/dL in 1993-1994 to almost 5.5 microg/dL in 1998. GM BLL in spring and summer ('nonheating' season) months were 10% higher than BLL in children tested in fall and winter ('heating' season), although air lead concentrations were lower in nonheating and higher in the heating season. For both the heating and nonheating seasons, there was a significant increase in the mean BLL with increasing air lead concentrations. Poor housing (odds ratio (OR): 1.82; 95% CI: 1.4, 2.3), two or more siblings in the family (OR: 3.12; 95% CI: 2.6, 3.7), lack of recreational trips outside the region (OR: 1.66; 95% CI: 1.47, 1.89), and the time child spent outdoors were associated with elevated BLL. Variables found to affect BLL in the Silesian children should be used to propose criteria to improve identification of children at risk and to focus prevention activities more effectively.