Blood lead levels are the best indicator of potential health risks: the amount of lead in a person's blood determines whether someone will experience lead's harmful health effects. Blood lead levels as low as 10 micrograms of lead per deciliter of blood (ug/dL) are associated with harmful effects on children's learning and behavior. Very young children (ages 1 and 2 years) are especially vulnerable to the effects of lead. The Centers for Disease Control and Prevention (CDC) considers a blood lead level greater or equal to 10 ug/dL to be an elevated blood lead level, indicating that steps should be taken to reduce ongoing lead exposure. For children with elevated blood lead levels, CDC recommends specific environmental, educational, and medical interventions according to their blood lead level.
Because lead risk varies considerably by geography, CDC recommends that state and local health departments assess local data on lead risks and develop lead screening recommendations for health care providers in their jurisdictions, focusing on one- and two-year old children. Many state screening plans can be accessed through health department web sites.
WHERE THE DATA COME FROM
The data used to compare states by the number of children with blood lead elevations were collected by states from 1997 - 2001 and reported annually to CDC. The states' annual surveillance data for children under the age of 6 years are based on reports of blood lead tests, usually from laboratories. As of 2001, 44 states, the District of Columbia, and New York City were reporting lead surveillance data to CDC; other states do not have childhood lead poisoning prevention programs affiliated with CDC. CDC published its report on these data in September 2003.
IMPORTANT LIMITATIONS AFFECT THE ACCURACY OF COMPARISONS
The number of identified cases for a state could be low for a number of reasons: the state could truly have a low rate of lead poisoning, it could have a low rate of testing children for lead poisoning, or, it could have a poor system for collecting and reporting data. Alternatively, a state could appear to have high rates of lead poisoning for other reasons, because, for example, primarily children at higher risk are screened, or its data include only information about elevated test results but not those that were normal. There are no data for the six states that do not report to CDC. Thus, it is impossible to use these data alone to assess relative lead poisoning rates across states or how well states are performing in identifying and tracking poisoned children.
Because of strict CDC definitions, these data may not comparable to similar data provided by other sources, including state health departments. Similar information may be defined or sorted differently. Any comparisons of these data to other reports from health departments or others should be made with care and attention to definitions. A more detailed discussion of data limitations can be found in CDC's article summarizing these data.