a Department of Emergency Medicine, University of Michigan , Ann Arbor , MI , USA.
b Department of Emergency Medicine, Hurley Medical Center , Flint , MI , USA.
Clin Toxicol (Phila). 2019 Sep;57(9):790-797. doi: 10.1080/15563650.2018.1552003. Epub 2019 Mar 14.
The toxicity of lead, like any xenobiotic, is directly linked to the duration of exposure and toxin concentration in the body. The elevation in blood lead levels (BLLs) in young Flint, Michigan children noted in time-periods before, and during the 18-month exposure to Flint River water (FRW) from 25 April 2014 to 15 October 2015 is well-known internationally. The length of time BLLs were elevated is unknown, yet key in understanding the potential health impact of the event. The objective of this study was to evaluate whether BLLs in Flint children were increased during the entire 18-month FRW exposure compared to similar earlier time periods. We conducted a retrospective study analyzing BLLs from Flint children aged 5 years and under. The geometric mean (GM) BLLs and percentages of BLLs ≥5.0 μg/dL in Period I: 25 April 2006 to 15 October 2007 (earliest timeframe available for study) and Period II: 25 April 2012 to 15 October 2013 (timeframe immediately before the water switch), were compared to Period III, 25 April 2014 to 15 October 2015 (FRW exposure). There were 5663 BLLs available for study. GM ± SE BLLs decreased from 2.19 ± 0.03 μg/dL in Period I to 1.47 ± 0.02 μg/dL in Period II [95% CI, 0.64, 0.79]; <.001 and to 1.32 ± 0.02 µg/dL during the FRW Period III [95% CI, 0.79, 0.95]; <.001. The percentage of BLLs ≥5.0 μg/dL decreased from Period I (10.6%) to Period II (3.3%) [95% CI, 5.7, 8.8]; <.001 and from Period I to Period III (3.9%) [95% CI, 5.0, 8.2]; =.002. The 0.6% increase from Period II to Period III was not statistically significant [95% CI, -1.9, 0.57]; =.30. Analyses of GM and percentages ≥5.0 μg/dL of BLLs do not support the occurrence of a global increase in BLLs in young children of Flint during the entire 18-month period of FRW exposure.
铅的毒性与任何异生物一样，直接与暴露时间和体内毒素浓度有关。2014 年 4 月 25 日至 2015 年 10 月 15 日，18 个月期间，密歇根州弗林特市儿童的血液铅水平（BLL）升高，这在国际上是众所周知的。BLL 升高的时间尚不清楚，但对于了解事件的潜在健康影响至关重要。本研究的目的是评估在整个 18 个月的 FRW 暴露期间，弗林特儿童的 BLL 是否升高。我们进行了一项回顾性研究，分析了 5 岁及以下弗林特儿童的 BLL。第 I 期（最早可用于研究的时间范围）2006 年 4 月 25 日至 2007 年 10 月 15 日和第 II 期（水切换前的时间范围）2012 年 4 月 25 日至 2013 年 10 月 15 日的几何平均值（GM）BLLs 和 BLLs≥5.0μg/dL 的百分比与第 III 期（FRW 暴露）进行了比较，2014 年 4 月 25 日至 2015 年 10 月 15 日。共有 5663 个 BLL 可用于研究。GM±SE BLL 从第 I 期的 2.19±0.03μg/dL 降至第 II 期的 1.47±0.02μg/dL[95%CI，0.64，0.79]；<.001和第 III 期 FRW 期间的 1.32±0.02μg/dL[95%CI，0.79，0.95]；<.001。BLLs≥5.0μg/dL 的百分比从第 I 期（10.6%）降至第 II 期（3.3%）[95%CI，5.7，8.8]；<.001，从第 I 期降至第 III 期（3.9%）[95%CI，5.0，8.2]；=.002。从第 II 期到第 III 期，BLL 增加了 0.6%，但无统计学意义[95%CI，-1.9，0.57]；=.30。GM 和 BLLs≥5.0μg/dL 的百分比分析不支持在整个 18 个月的 FRW 暴露期间，弗林特幼儿的 BLL 普遍升高。
