Lead Poisoning in Children: Early Detection, Intervention and Prevention
Part I: Overview
Childhood lead poisoning is a significant environmental health problem, yet it is entirely preventable. Lead poisoning prevents children from reaching their full potential. Children ages six years old and younger are particularly susceptible to the effects of lead poisoning. Ingestion of lead, through hand-to-mouth behavior, is the primary pathway of exposure in children.
In 2014, the Centers for Disease Control and Prevention (CDC) changed their "level of concern" from 10 micrograms of lead per deciliter whole blood (µg/dL) to 5 µg/dL. This is the reference level at which CDC recommends public health actions be initiated. According to the CDC website, "There are approximately half a million U.S. children ages 1-5 with blood levels above 5 µg/dL. No safe blood lead level in children has been identified. Lead poisoning can affect nearly every system in the body. Because lead poisoning often occurs with no obvious symptoms, it frequently goes unrecognized." Lead poisoning can cause learning disabilities, behavioral problems and, at very high levels, seizures, coma, and even death.
CDC's Childhood Lead Poisoning Prevention Program is committed to the Healthy People 2020 overall goal (EH-8) of reducing blood lead levels in children using the baseline measurement of 0.9 percent of children having Elevated Blood Lead Levels (EBLL) and elimination of EBLL by 2020. Additionally, another supporting goal is to reduce the mean blood lead levels in children aged 1 to 5 years from a baseline of 1.5 to 1.4mcg/dL. Blood lead levels are measured in micrograms per deciliter written either as mcg/dL. One problem with the goals as written is that elevated blood lead level is not clearly defined.
The CDC continues to assist state and local childhood lead poisoning prevention programs, to provide a scientific basis for policy decisions, and to ensure that health issues are addressed in decisions about housing and the environment (Source: CDC Lead).
Most experts consider old lead-containing house paint to be the major source of lead for children, particularly young children under the age of 6 years.
However, MANY other sources also pose a risk and should be addressed as well. Some other sources are:
- bare soil
- herbal remedies or spices containing lead
- hobbies performed by parents
- "take-home" lead from a parent's occupation
- lead-containing toys, strings of lights, and other household items
Most people in the health care community attribute the decrease in reported EBLLs to:
- increased screening
- education and general public awareness
- ongoing reductions in environmental lead due to bans on leaded paint and gasoline
- increased activities to remove lead from the environment (i.e., replacement of lead-painted housing components such as old windows or doors)
Nevertheless, children without health insurance, on MA or MinnesotaCare, are often missed. They often are not seen for routine preventive care, and thus are not being tested for lead as required. Cost is frequently an issue for families or property owners looking to perform lead hazard reduction activities on their homes or property.
The incidence of lead poisoning is continuously decreasing, even as lead testing is increasing. That suggests that efforts to eliminate lead poisoning are on track. However, at the current rates, lead poisoning likely will not be eliminated in time for the 2020 goals. Testing of C&TC-eligible children has increased since 1998 but not every child is seen for preventive care, so there is no safety net to ensure testing of all children. More data can be found on the MDH Lead Poisoning Prevention website.
Blood Lead Screening in Minnesota Children
Despite the fact that the average overall BLL in the U.S. was less than 2 mcg/dL in 2005 (down from 12.8 mcg/dL in 1976) lead exposure is still a significant problem both in the U.S. and in Minnesota. This is especially true for young children because the adverse effects of EBLLs on an immature nervous system are dramatic and often irreversible. Because symptoms of EBLLs are not always initially apparent or visible, the only way to know if a child has had lead exposure is by lab testing of the blood. This is done via capillary access with a finger stick and if there is an EBLL, a confirmation venous draw is then required.
In Minnesota, targeted screening based on established risk factors is currently recommended for most areas of the state. According to the 2015 Minnesota Blood Lead Surveillance Report, "universal testing is recommended for children residing in Minneapolis and St. Paul and those recently arriving from other major metropolitan areas or other countries. Testing is also recommended for children receiving Medicaid." The goal is to test all children at risk for exposure to lead.
The number of children tested for lead in Minnesota increased dramatically between 2000 and 2008 and has recently begun to decrease, with 87,728 children tested in 2015 (Figure 1).
Figure #1: Number of Children Tested (Less Than 6 Years of Age)
MDH maintains a blood lead information system (BLIS) for the purpose of monitoring trends in BLL in adults and children in Minnesota. Figure 2 shows that the number of EBLL cases in Minnesota children has continued to decrease over the years . According to the Minnesota Blood Lead Surveillance Report, in 2014 there were 2,643 Minnesota children with blood lead levels of 5 µg/dL or greater, and 96 children had venous blood lead levels of 15 µg/dL or greater.
Additional data on capillary testing can be found in the 2016 Blood Lead Surveillance Report (PDF).
Figure #2: Number of Children with Elevated Blood Lead Levels