Abstract

Background:

No safe level of lead in blood has been identified. Blood lead testing is required for children on Medicaid, but it is at the discretion of providers and parents for others. Elevated blood lead levels (EBLLs) cannot be identified in children who are not tested.

Objectives:

The aims of this research were to identify determinants of lead testing and EBLLs among North Carolina children and estimate the number of additional children with EBLLs among those not tested.

Methods:

We linked geocoded North Carolina birth certificates from 2011–2016 to 2010 U.S. Census data and North Carolina blood lead test results from 2011–2018. We estimated the probability of being screened for lead and created inverse probability (IP) of testing weights. We evaluated the risk of an EBLL of $\ge 3\mathrm{\mu }\mathrm{g}/\text{dL}$ at $<30\text{months}$ of age, conditional on characteristics at birth, using generalized linear models and then applied IP weights to account for missing blood lead results among unscreened children. We estimated the number of additional children with EBLLs of all North Carolina children using the IP-weighted population and bootstrapping to produce 95% credible intervals (CrI).

Results:

Mothers of the 63.5% of children (402,002 of 633,159) linked to a blood lead test result were disproportionately young, Hispanic, Black, American Indian, or on Medicaid. In full models, maternal age $\le 20\mathrm{y}$ [$\text{risk\hspace{0.17em}ratio\hspace{0.17em}}\left(\text{RR}\right)=1.10$; 95% confidence interval (CI): 1.13, 1.20] or smoking ($\text{RR}=$1.14; 95% CI: 1.12, 1.17); proximity to a major roadway ($\text{RR}=$1.10; 95% CI: 1.05, 1.15); proximity to a lead-releasing Toxics Release Inventory site ($\text{RR}=$1.08; 95% CI: 1.03, 1.14) or a National Emissions Inventory site ($\text{RR}=$1.11; 95% CI: 1.07, 1.14); and living in neighborhoods with more housing built before 1950 ($\text{RR}=$1.10; 95% CI: 1.05, 1.14) or before 1940 ($\text{RR}=$1.18; 95% CI: 1.11, 1.25) or more vacant housing ($\text{RR}=$1.14; 95% CI: 1.11, 1.17) were associated with an increased risk of EBLL, whereas overlap with a public water service system was associated with a decreased risk of EBLL ($\text{RR}=$0.85; 95% CI: 0.83, 0.87). Children of Black mothers were no more likely than children of White mothers to have EBLLs ($\text{RR}=$0.98; 95% CI: 0.96, 1.01). Complete blood lead screening in 2011–2018 may have identified an additional 17,543 (95% CrI: 17,462, 17,650) children with EBLLs $\ge 3\mathrm{\mu }\mathrm{g}/\text{dL}$.

Discussion:

Our results indicate that current North Carolina lead screening strategies fail to identify over 30% (17,543 of 57,398) of children with subclinical lead poisoning and that accounting for characteristics at birth alters the conclusions about racial disparities in children’s EBLLs. https://doi.org/10.1289/EHP10335

中文翻译：

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2011-2018 年北卡罗来纳州儿童血铅筛查模式和血铅水平——谁被检测，谁被遗漏？

摘要

背景：

尚未确定血液中铅的安全水平。参加 Medicaid 的儿童需要进行血铅检测，但其他人则由提供者和家长自行决定。未经测试的儿童无法确定血铅水平升高 (EBLL)。

目标：

本研究的目的是确定北卡罗来纳州儿童铅检测和 EBLL 的决定因素，并估计未接受检测的儿童中额外患有 EBLL 的儿童数量。

方法：

我们将 2011-2016 年地理编码的北卡罗来纳州出生证明与 2010 年美国人口普查数据和 2011-2018 年北卡罗来纳州血铅检测结果联系起来。我们估计了铅筛查的概率，并创建了测试权重的逆概率 (IP)。我们评估了 EBLL 的风险$\ge 3\mathrm{\mu }\mathrm{G}/\text{dL}$在$<30\text{月}$年龄，以出生时的特征为条件，使用广义线性模型，然后应用 IP 权重来解释未筛查儿童的血铅缺失结果。我们使用 IP 加权人口和自举产生 95% 的可信区间 (CrI) 估计了所有北卡罗来纳州儿童的 EBLL 额外儿童数量。

结果：

与血铅检测结果相关的 63.5% 的儿童（633,159 名中的 402,002 名）的母亲多为年轻、西班牙裔、黑人、美洲印第安人或接受医疗补助。在完整模型中，产妇年龄$\le 20\mathrm{是的}$[$\text{风险比\hspace{0.17em}}\left(\text{RR}\right)=1.10$; 95% 置信区间 (CI): 1.13, 1.20] 或吸烟 ($\text{RR}=$1.14；95% CI: 1.12, 1.17); 靠近主要道路（$\text{RR}=$1.10；95% CI: 1.05, 1.15); 靠近铅释放毒物排放清单站点（$\text{RR}=$1.08; 95% CI: 1.03, 1.14) 或国家排放清单站点 ($\text{RR}=$1.11；95% CI: 1.07, 1.14); 并居住在 1950 年以前建造的房屋较多的社区（$\text{RR}=$1.10；95% CI: 1.05, 1.14) 或 1940 年之前 ($\text{RR}=$1.18；95% CI: 1.11, 1.25) 或更多空置房屋 ($\text{RR}=$1.14；95% CI：1.11, 1.17）与 EBLL 风险增加相关，而与公共供水服务系统重叠与 EBLL 风险降低相关（$\text{RR}=$0.85; 95% CI：0.83, 0.87)。黑人母亲的孩子患 EBLL 的可能性并不比白人母亲的孩子高（$\text{RR}=$0.98; 95% CI：0.96, 1.01)。2011-2018 年的完整血铅筛查可能发现了另外 17,543 名（95% CrI：17,462、17,650）名 EBLLs 儿童$\ge 3\mathrm{\mu }\mathrm{G}/\text{dL}$.

讨论：

我们的结果表明，目前的北卡罗来纳州铅筛查策略未能识别出超过 30%（57,398 名中的 17,543 名）患有亚临床铅中毒的儿童，并且考虑出生时的特征会改变关于儿童 EBLL 种族差异的结论。https://doi.org/10.1289/EHP10335