Hernán F Gómez, Dominic A Borgialli, Mahesh Sharman, Keneil K Shah, Anthony J Scolpino, James M Oleske, John D Bogden

We evaluated the increases in blood lead levels (BLLs) observed in young children in Flint, Michigan, during their exposure to corrosive Flint River water during the years 2014 and 2015 and compared their BLLs to those of Flint children measured during the years 2006-2013 and 2016. This was a retrospective study design using BLLs extracted from databases from 2006 to 2016. We analyzed a population sample of 15 817 BLLs from children aged ≤5 years with potential exposure to contaminated Flint River water. Percentages of BLLs ≥5.0 µg/dL and geometric mean (GM) BLLs were analyzed over time. A significant decline in the percentages of BLLs ≥5.0 µg/dL from 11.8% in 2006 to 3.2% in 2016 was observed (P < .001). GM ± SE BLLs decreased from 2.33 ± 0.04 µg/dL in 2006 to 1.15 ± 0.02 µg/dL in 2016 (P < .001). GM BLLs increased twice: from 1.75 ± 0.03 µg/dL to 1.87 ± 0.03 µg/dL (2010-2011) and from 1.19 ± 0.02 µg/dL to 1.30 ± 0.02 µg/dL (2014-2015). Overall, from 2006 to 2016, there was a 72.9% decrease in the percentage of children with BLLs ≥5.0 µg/dL and a 50.6% decrease in GM BLLs. These findings suggest that the 11 year trend of annual decreases in BLLs in children in Flint, Michigan, reversed to a degree consistent with random variation from 2010 to 2011, and again during the exposure to Flint River water in 2014-2015. Historically, public health efforts to reduce BLLs of young children in Flint have been effective over the 11-year period studied.