Despite four decades of public health efforts to minimize children's exposure to lead, high percentages of unsafe blood lead levels are still found in children in numerous regions of the United States, according to a new study by researchers at Quest Diagnostics (NYSE: DGX), the world's leading provider of diagnostic information services.

Published online in the Journal of Pediatrics, the six-year study examined 5,266,408 blood lead levels (BLLs) test results of infants and children under age six in all 50 states and the District of Columbia. The Quest Diagnostics Health Trends™ study is believed to be the largest analysis of BLL test results in children in the United States.

While there is no safe blood lead level in children, the Centers for Disease Control and Prevention (CDC) has identified a blood lead level equal to or greater than five micrograms per deciliter as a threshold to identify children with elevated blood lead levels. The study found that greater than 3.0% of children nationally had blood lead levels at or above this level. High blood lead levels were greater for boys (3.1%) than girls (2.8%), a slight, but statistically significant difference. Despite an unexplained modest increase during the last 12-months of the study, blood lead levels overall declined in children during the six-year period ending in April 2015.

However, on a regional basis, high percentages of infants and children had blood lead levels equal to or greater than five micrograms per deciliter (high BLLs). In six regions categorized by ZIP code, more than 14 percent of specimens tested had high BLLs. These include three regions in New York (Syracuse, Buffalo and Poughkeepsie), two in Pennsylvania (York and Oil City) and one in Ohio (Cincinnati). The eleven regions with the largest proportions of specimens with very high BLLs (equal to or greater than ten micrograms of per deciliter), were also in New York (Syracuse, Buffalo, Poughkeepsie, Niagara Falls, Binghamton), Pennsylvania (York, Oil City, Reading, Erie), and Ohio (Cincinnati, Cleveland).

The analysis also examined rates by states, finding that those with the highest proportion of high BLLs were Minnesota (10.3%), Pennsylvania (7.8%), Kentucky (7.1%), Ohio (7.0%), and Connecticut (6.7%). California and Florida had the lowest rate of high BLLs (1.4% and 1.1%, respectively) and very high BLLs (0.2% and 0.1%).

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