The Centers for Disease Control and Prevention (CDC) has identified lead exposure as one of the most preventable environmental health threats to children in the United States.1 However, despite the preventable nature of lead poisoning, the National Health and Nutritional Examination Survey data from 1999 to 2010 indicate that approximately 535 000 US children aged 1 to 5 years have blood lead levels (BLLs) of 5 μg/dL or more.2 Exposure to lead can have profound detrimental effects on early childhood development.3 It is known to cause neurological damage in young children and is associated with poorer performance in school, lower IQ, attentional deficits, and juvenile delinquency.4 Even more compelling is the evidence that these outcomes can occur even at low BLLs and have long-reaching effects on the future outcomes of children.4 The impacts, however, are not equal, disproportionately placing children living in poverty and ethnic and racial minorities at greater disadvantages.5,6
In July 2006, the Southern Nevada Health District (SNHD), in collaboration with other partner agencies, was awarded a grant from the CDC to establish the Childhood Lead Poisoning & Prevention Program (CLPPP), the first of its kind in the state. The program aimed to increase screening, develop the infrastructure to identify and respond to children with elevated blood lead levels (EBLLs), and improve epidemiological lead surveillance data in Clark County, Nevada. Clark County is the most populous area of the state located at the most southern tip and a county with a historically low blood lead testing rate. Clark County is home to more than 160 000 children younger than 6 years of which approximately 25% are living below poverty. Of those children in poverty, 30% are black or Hispanic children. Although more than 20% of the housing stock was built before 1980, traditional sources of lead, such as lead paint, are not the only sources of exposure to children living in the area. For instance, imported products, imported candies, folk remedies, pottery, ceramics, and other items such as pewter key chains and bathtub tiles have been implicated in EBLL cases.7
Despite the array of sources that can expose children to lead, screening rates for children younger than 6 years in Clark County prior to the CLPPP were about 2%. A study conducted by Haboush-Deloye et al,8 who assessed barriers to lead screening in Nevada from a sample of pediatric providers, found that providers felt it was not necessary, it was not a state mandate, it was not a standard practice in the state, or that only children in high-risk housing should be tested. Given that Clark County has a rapidly growing population of ethnically diverse communities and there are a variety of sources of lead exposure, it is important to increase screening rates to identify children who may be exposed to lead and to identify communities that may be at an increased risk of exposure. This article aims to assess the impact of a federally funded CLPPP in increasing and identifying children with EBLLs.
Strategies to increase BLL screening in Clark County by Southern Nevada CLPPP
The CLPPP implemented a variety of strategies during the project period from 2006 to 2011 to increase BLL screening through provider education, community outreach, and increasing methods to conduct rapid BLL tests in targeted communities.
A 2-pronged approach was utilized to encourage pediatricians to screen for lead in children younger than 6 years. The first approach included the distribution of provider-specific informational materials, such as BLL screening recommendations and continuing education opportunities, to more than 1400 practicing pediatricians. Providers were also given materials to distribute to families. The second approach, provider outreach, focused on conducting in-person office visits with pediatricians serving low-income families and highly concentrated Hispanic populations due to the risk of nontraditional sources of lead exposure in Hispanic communities. One-on-one visits were used to establish relationships with providers serving our high-risk communities while encouraging them to conduct BLL screening as recommended by CDC guidelines, at 12 and 24 months of age, particularly for children on Medicaid.9
The second approach to increase lead screening in children was community outreach to parents and child-serving organizations to encourage parents and families to have their children tested by their provider. Since time and resources were limited, community outreach was targeted to areas thought to be at higher risk based on existing research. These areas included areas with the oldest housing and areas densely populated by low-income minority populations. CLPPP staff attended approximately 32 events held in the community, including “back to school” fairs, Head Start centers, and church events in the target locations in Clark County (Table 1).
Finally, the third approach was to reduce barriers to lead screening by utilizing a LeadCare II blood lead analyzer. This portable screening device, which requires the collection of a capillary specimen via a finger stick, was acquired and approved for use in the state of Nevada in February 2008. CLPPP staff utilized the LeadCare II to conduct screenings at the health district and targeted community sites during years 4 and 5 of the grant.
Blood lead testing data and statistical analyses
To examine the number of children screened prior to the start of the program, during the 5 years the program was funded, and post–federal funding, data were obtained for each time point. Screening numbers for children younger than 72 months for the baseline year were provided by the SNHD in aggregate. During the project years, de-identified data from July 1, 2006, to June 30, 2011, for Clark County were provided by the SNHD for secondary data analysis at the end of the project period. SNHD staff exported data from their internal system into a CVS file that was imported into SPSS for analysis. Surveillance data included sex, birth date, race/ethnicity, type of test conducted (capillary or venous), screening location, and screening results. Post–federal funding data were only available from October 1, 2016, to June 30, 2017. The gap in data is a result of a change in data systems at the SNHD.
All data used to calculate frequencies of children tested for the baseline period (July 1, 2005-June 30, 2006), per project year (July 1-June 30 per year), and for post–project years (October 1, 2016-September 30, 2017) included results of the child's first blood test except for children with BLL of 10 μg/dL or more. Children with a BLL of 10 μg/dL or more may have received both venous and capillary tests and were counted once during the month their EBLL was first confirmed via a venous draw.
SPSS version 24 was used to run descriptive statistics of testing data and a 2-tailed χ2 test with a .05 significance level to examine the relationship between a child's gender, race, and BLL category. Ethical approval was obtained from the University of Nevada Las Vegas institutional review board.
Number of children tested
Available baseline data from 2005 to 2006 indicated that only 4180 children younger than 6 years were tested for BLLs in Clark County, Nevada. Once the project commenced in 2006, an increase in testing occurred in just the second year, with a total of 9304 children younger than 6 years tested, which is an increase of 122.6%. Between July 1, 2006, and June 30, 2011, testing ranged from 3811 to 10 872 children receiving a blood lead test per year (Figure). The average number of children screened during the 5 project years (n = 8606) was a substantial increase compared with both the baseline data from 2005 to 2006 (n = 4180) and the data once CLPPP was no longer funded (n = 5541).
Characteristics of children tested during project years
A total number of 43 028 children younger than 6 years were screened during the project period, of which 21 673 (51.2%) were male, 21 009 (48.4%) were female, and 0.4% listed no specific sex. Unfortunately, less than 5% of BLL reports included race and ethnicity data. The majority of the race and ethnicity data were collected from the LeadCare II devices that were used by CLPPP staff to conduct screenings during the last 2 project years (Table 2). Race and ethnicity data were available for 2083 children, of which 30.6% identified as non-Hispanic, 52% identified as Hispanic, and 17% did not report ethnicity. The population represents 20.8% of African American children and 21.1% Caucasian children. However, in terms of race, the majority (50.5%) are unknown.
Blood lead level
BLL is reported respectively by BLL less than 5 μg/dL, 5 μg/dL or more to less than 10 μg/dL, and 10 μg/dL or more for each corresponding year of the CLPPP (Figure). Of the 43 028 blood lead screenings conducted during the project period, 1.5% had BLLs of 5 μg/dL or more and less than 10 μg/dL and less than 1% had levels of 10 μg/dL or more. The distribution of levels of lead in the blood did not show any significant difference by sex, P(χ2 > 5.451) = .141 (Table 3). Data were not analyzed on the basis of race and ethnicity due to limited reporting.
The purpose of this article was to assess the importance of federally funded CLPPP, particularly in areas that have historically low lead screening. To our knowledge, this is the first study that directly evaluates the impact of efforts made by a CLPPP to increase BLL screening and highlights the current challenges to protecting children's health through lead poisoning prevention efforts.
Federal support to establish the CLPPP played a vital role in increasing the number of children tested for lead. While we are unable to discern whether increases in screening resulted from an increase in the proactivity of medical providers to screen, in the proactivity of parents to request their children to be screened, or both, we do know that lead screening rates were at the highest they have ever been documented in the county. We postulate that increases in screening are a result of a combination of targeted outreach and education, one-on-one contact, and community presentations, all of which focused on encouraging parents to have their children screened and encouraging doctors to follow CDC recommendations for lead screening. Other activities employed by CLPPP staff such as implementing the use of the LeadCare II helped reduce cost and barriers associated with off-site testing and may have eased any parental concerns of their child having a venous test.
Despite these accomplishments, a number of challenges are still present. First, the average number of children screened during the project years represents only 5% of all children younger than 6 years living in Southern Nevada. To date, lead screening in Nevada has decreased to less than 3% of all children residing in the state, indicating the importance of an established, coordinated, and funded CLPPP in sustaining efforts to identify children affected by lead. This is of particular importance for states that have low blood screening rates to begin with and are faced with perceptions that lead is no longer a problem or not a problem in their state. In 2017, Roberts and colleagues10 published an article examining blood lead screening data across the country and determined that approximately 1 in 3 children believed to have EBLL goes undetected, with underreporting highest in western states. In addition, Robert and colleagues10 found that nationwide, approximately 50% of cases of EBLLs are missed because of insufficient screening. Lack of screening in Nevada and similar states, especially in the western United States, indicates that lead poisoning is no longer viewed as a threat.
Second, in addition to low screening rates, there is a severe lack of demographic variables, such as race, ethnicity, and zip code, collected and reported. This makes it challenging to use local data to adequately identify vulnerable populations and communities in Clark County.
Third, over the course of all 5 project years, 1.5% (n = 641) had a BLL of 5 μg/dL or more and less than 1% (n = 90) of children tested had a BLL greater than 10 μg/dL. During the implementation of the CLPPP, only children at or above a BLL of 10 μg/dL had a follow-up evaluation by a nurse and by a lead-certified risk assessor to provide case management and to identify lead hazards in the home. In 2012, post-CLPPP, the Advisory Committee on Childhood Lead Poisoning Prevention recommended lowering the reference level for lead in the blood from 10 to 5 μg/dL.4,11,12 The new recommendation now removes the “level of concern” terminology to align with the new evidence that there is no safe level of lead in the blood.4 This means that more than 600 children who call Southern Nevada home had a BLL that is considered to be at or above the reference value in which some type of follow-up should occur under current recommendations.
Low screening rates in Southern Nevada combined with a lowered reference value of lead in the blood have far-reaching implications for young children in this community and those living in low screening states. For example, research has demonstrated that even low levels of lead exposure are directly related to negative cognitive outcomes.13–16 Chronic exposure to lead at levels below 10 μg/dL has been found to have a greater impact on IQ, with a loss of 3.9 to 7.4 IQ points compared with 2.5 to 3.0 IQ points at BLLs between 10 and 30 μg/dL.17 Impacts in learning will continue to widen the achievement gap between low-income children and children of ethnic minority backgrounds.6 In addition, a growing body of scientific research indicates that lead exposure can occur from nontraditional sources such as leaded “Mexican candies, folk remedies, imported pottery and ceramics, pewter key chains, and bathtub tiles.”7(p487),18–20 These nontraditional routes of exposure offer opportunities for a child to be poisoned and will remain undetected if CDC recommendations for lead screening are not adhered to. There is a significant need to increase screening in children to identify EBLLs and reduce the risk of continued exposure to traditional and nontraditional sources.
In Southern Nevada, we have seen a substantial decline in lead screening rates, leaving a greater gap in the identification of children with EBLLs. Without sufficient screening, it is impossible to determine the true prevalence of EBLLs in young children both locally and nationally, and this lack of knowledge puts children at unnecessary risk that could result in lifelong negative impacts.
There are a few limitations that should be considered for this study. First, screening data for all time points examined in this study were not available from the local health district due to a change in their electronic storage system. Therefore, post-CLPPP data are not available until 2016-2017. Second, race and ethnicity data were not consistently collected throughout all project years. The most accurate race/ethnicity data are from project years 4 to 5 for those children screened using the portable LeadCare II. The majority of the screening conducted with the LeadCare II was by CLPPP project staff who could ensure that race and ethnicity data were collected. Without race and ethnicity data, it is not possible to compare screening rates across racial and ethnic groups or to determine whether certain groups are at a higher risk of exposure. Future efforts should include the collection of race and ethnicity data for all blood lead screening results to accurately determine whether a certain population is at a higher risk of exposure. Finally, because of targeted screening campaigns, the population screened through CLPPP is not generalizable to all of Clark County or Nevada as a whole. To maximize limited resources, outreach and screening efforts were targeted to children considered most at risk for lead exposure. However, because of the limited data obtained on race and ethnicity, as well as the small percentage of eligible children tested, this cannot be confirmed. Finally, while it is required to report all BLL data in Clark County, little is known to what extent providers who use portable systems, such as the LeadCare II, report results to the health district. Therefore, low screening numbers could be due to underreporting rather than a lack of screening.
Implications for Policy & Practice
- Our study highlights the importance of federal support to enhance the ability of states and local communities to identity and respond to children who present with EBLLs.
- Provider engagement and community education are successful methods to increase screening rates in communities. However, these efforts must be maintained to sustain screening practices.
- While universal screening is no longer recommended in most states,21 it is important to conduct sufficient screening in states with historically low rates in order to determine local risk factors for lead exposure.
Our study highlights the direct success of federal initiatives to address childhood lead poisoning through prevention, identification, and interventions. The implementation of the CLPPP allowed for cross-sector collaboration to develop a plan to better determine the extent of lead poisoning in children in Southern Nevada and to develop a plan to eliminate lead poisoning. CLPPP funding directly led to the ability to develop the infrastructure to support activities that did not exist in Southern Nevada. Federal support contributed to increasing screening rates in children who call Southern Nevada home, increasing awareness about lead as an environmental threat to young children, developing a systematic way to identify lead-based hazards in homes, and responding to cases of EBLLs.20
These findings should be used to stimulate future research to evaluate the impact of the loss of federal funding on childhood lead poisoning prevention efforts. These findings should also stimulate the implementation of policies and practices that continue to enhance the prevention of childhood lead poisoning such as continued surveillance, mandated electronic reporting, and mandated collection and reporting of demographic variables such as race and ethnicity.
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