Epidemiological investigation to assess environmental contributions to childhood blood lead levels

Reduction in childhood blood lead levels has been one of the most successful public health efforts in history. However, there is ongoing evidence that declines in cognition and social behavior occur at levels well below 10 µg/dL and the effects of lead exposure are irreversible. This body of work will address current and continuous sources of lead in the environment and its potential impact on childhood blood lead levels. Toxic Release Inventory (TRI) lead emissions and ambient air lead estimated by the National Air Toxics Assessment (NATA) were used to assess associations between environmental lead and childhood blood lead levels (n = 3,223) measured in the National Health and Nutrition Examination Survey (1999-2006). After adjustment (gender, race, age in months, percent pre-1950 housing, reference adult’s education, poverty income ratio, region and survey cycle) a 10,000 lb/mi2 increase in TRI resulted in a 1.13% (95%CI: 0.45, 1.81) increase in blood lead. Neither TRI nor NATA estimates were significantly associated with blood lead after adjusting for cotinine and floor lead dust.\ud Two additional studies were conducted with a specific focus on children living in Pennsylvania and New Jersey. The first study assessed if living within 3km of an airport was associated with elevated blood lead levels (n = 493,956). After adjustment for percent pre-1950 housing, poverty and race, gender, age in months, and industrial emissions, children living near an airport (n = 25,684) did not have a higher prevalence of elevated blood lead (≥ 5µg/dL) than children living further away. Finally, a geospatial regression was performed to determine the distribution of children with elevated blood lead levels (n = 855,291). Children living in large rural towns and isolated rural towns have a higher prevalence of elevated blood lead levels than urban areas after adjusting for percent male, pre-1950 housing, poverty, race, and industrial air lead emissions. Other sources such as neighborhood lead contamination and residential lead dust may contribute to childhood blood lead levels. The public health significance of these studies is to determine current sources of environmental lead so primary prevention programs can be implemented to further limit exposures in children.\u