At a glance
CDC uses available data and generates statistics to track progress towards the elimination of childhood lead poisoning in the United States. Find information on these data sources and access national and state blood lead surveillance data.
Overview
CDC collaborated with the Council of State and Territorial Epidemiologists (CSTE) to develop a national surveillance system. This system monitors blood lead levels (BLLs) in the United States.
In 1995, reporting of blood lead levels became the first non-infectious condition to be notifiable at the national level. This information is used to monitor individual case management and identify local program needs and high-risk areas to target preventive interventions.
At the state or local level, the primary source of blood lead surveillance data are usually the state-based Childhood Lead Poisoning Prevention Program (CLPPP) and/or the state-based Adult Blood Lead Epidemiology & Surveillance (ABLES) Program. These programs are responsible for collecting, managing, and reporting data. This ensures that children and adults with lead in their blood receive appropriate follow-up and management. CDC supports development of the Healthy Homes and Lead Poisoning Surveillance System (HHLPSS) as a data management platform for blood lead surveillance.
Blood lead surveillance data are a valuable resource for program management. However, these data have limitations. First, data from these programs are restricted to individuals targeted for blood lead testing by healthcare providers. Healthcare providers usually test children and adults at a high risk for lead exposure. Because of this, the people tested are not representative of the entire U.S. population.
Additionally, state requirements for blood lead testing and reporting vary based on local conditions. Due to this, the data are not comparable across locations or generalizable at the national, state, or local level.
NHANES is another source of data for estimating the number of children and adults with lead in their blood. These surveys provide national estimates of the prevalence of lead in the blood among children and adults over time. However, it cannot provide information at the state or local level.
These surveys also do not directly measure incidence and the data cannot be used to follow short-term trends. NHANES blood lead data are used to monitor the nation's progress in meeting the Healthy People Objectives.
CDC’s childhood lead poisoning data
A blood lead test is the best way to measure lead exposure. Children are given a blood test to determine the level of lead in their blood.
The amount of lead in blood is referred to as blood lead level (BLL). BLLs are measured in micrograms of lead per deciliter of blood (μg/dL).
There is no known safe BLL. Exposure to lead can seriously harm a child's health. Millions of children are being exposed to lead in their homes, increasing their risks for:
- Damage to the brain and nervous system
- Slowed growth and development
- Learning and behavior problems (e.g., reduced IQ, ADHD, juvenile delinquency, and criminal behavior)
- Hearing and speech problems
CDC began collecting childhood blood lead surveillance data in April 1995.
CDC funds 51 state and local health departments for lead surveillance. As part of their funding agreement, awardees (recipients) are required to report data to us on a quarterly basis. Data reporting to CDC is voluntary for states that are not funded by CDC.
- The 48 funded states are Alabama, Alaska, Arizona, California, Colorado, Connecticut, Delaware, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Montana, Nebraska, Nevada, New Hampshire, New Jersey, New Mexico, New York State, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming.
- We also fund Washington, DC, New York City, and Puerto Rico.
CDC uses data from states to prepare the State Surveillance and National Surveillance data sets. These data are from funded states and local jurisdictions with public health surveillance authority.
About the data
CDC recipients annually report:
- Data on blood lead testing and follow-up of children identified with BLLs at or above the reference value.
- Lead hazard identification, control, and abatement activities in their jurisdictions
- Proposed interventions for high-risk areas
States collect the lead poisoning data through a variety of sources including:
- Both public and private labs
- State and local housing authorities
- State and local environmental protection agencies
- State and local education agencies
Limitations
Analyses and generation of surveillance reports require considerable time and human intervention. Therefore, data are not always sent to CDC in a timely manner. Even so, about 3 million blood lead tests are received by CDC each year. The data is grouped into a reportable surveillance format after careful cleaning and deduplication.
Once CDC gets and cleans the data, the data is processed and parsed into State Surveillance and National Surveillance data sets.
The childhood BLL data on CDC's website are not a population-based estimate. These data are not representative of a whole county or a whole state, they are designed to target the highest-risk areas. Programs work hard to test children most likely to have high BLLs.
Programs vary in the number of children tested and the number of children identified with blood lead levels at or above the reference value.
Percentage comparisons can be affected by:
- County size,
- Number of children tested within the counties, and
- Number of children in the counties who are reported BLLs at or above the reference value. For example, some counties may have a small number of children tested, but many of those tested have BLLs at or above the reference value.
Some statistics could underestimate the number of children with lead exposure because not all children are tested.
Use
Health agencies using CDC's supported surveillance system or other childhood lead poisoning surveillance and data collection system can:
- Identify remaining at-risk geographic areas
- Identify at-risk children through targeted testing and prioritization of limited resources
- Identify emerging sources of exposure and inform strategic plans to remove or reduce sources
- Evaluate timeliness and efficacy of case management services available to children with lead poisoning and work with inspectors and risk assessors to ensure safe living environments
- Target pediatric healthcare provider education efforts
About NHANES
NHANES is a population-based survey. The survey is used to assess the health and nutritional status of adults and children in the United States. CDC's state-based data are not comparable to data in NHANES.
CDC analyzed NHANES data of the blood lead values among U.S. children ages 1-5 years from 2015-2016 and 2017-2018 NHANES cycles to determine the 97.5th percentile of blood lead distribution in children. This helped to determine the reference value at 3.5 µg/dL.
Declining BLLs
BLLs have continued to decline in the last 30 years, even in the most high-risk areas. The overall declining in children detected with BLLs at or above the reference value is in keeping with the national population-based estimate from NHANES, which has also declined over time.
The decrease is most likely a result of an intense coordinated effort to control or eliminate lead sources in children’s environments by:
- Government officials
- Healthcare and social service providers
- The communities most at risk