According to a new report released last month by the Centers for Disease Control and Prevention (CDC), more than half a million US children have elevated levels of lead in their blood. A new report published online by researchers at Johns Hopkins University (Baltimore, Maryland) on May 13 in the journal Pediatrics has found a link between the presence of lead in the blood and reading readiness at kindergarten entry. The finding goes beyond reading skills because reading is an early marker of school performance.
In the past, the CDC had used a higher threshold, 10 micrograms/deciliter or greater, to identify children with elevated blood lead levels; however, last year, the recommendations changed to include children with levels at or above 5 mg/dl because these levels are higher than normal. The reason for lowering the level of concern was to identify children with high levels earlier so that action can be taken to reduce their lead exposure. According to the CDC, these children need medical treatment, known as chelation therapy, for lead exposure if their blood lead levels reach 45 mg/dl. Even low levels of lead in the blood have been linked with lower IQs and attention problems; furthermore, there is no safe level of lead exposure.
The new study evaluated the relationship between blood lead levels and reading readiness at kindergarten entry in a diverse urban school population. Kindergarten reading readiness test scores for children attending public kindergarten in Providence, Rhode Island were reviewed; they were linked to state health department records of blood lead testing by using individual identifiers. The 3,406 children reviewed were 59% Hispanic. For each child, the average blood lead level was estimated by using all previously reported blood lead levels. Analyses were adjusted for gender, age, year enrolled, race, child language, and free/reduced lunch status as a measure of socioeconomic status.
The researchers found that the average blood lead level was 4.2 µg/dL; 20% of children had at least blood sample of blood level of 10 µg/dL. Compared with children with blood lead levels of 5 µg/dL or less, the adjusted prevalence ratios for failing to achieve the national benchmark for reading readiness were 1.21 (1.19 to 1.23) and 1.56 (1.51 to 1.60) for children with blood lead levels of 5 to 9 and more than 10 µg/dL, respectively. On average, reading readiness scores decreased by 4.5 points for children with blood lead levels of 5 to 9 and 10 or more µg/dL, respectively, compared with BLLs less than 5 µg/dL.
The investigators concluded that blood lead levels well below 10 µg/dL were associated with lower reading readiness at kindergarten entry. They noted that the high prevalence of elevated BLLs warrants additional investigation in other high-risk US populations. Results suggest benefits from additional collaboration between public health, public education, and community data providers.
The Los Angeles County Childhood Lead Poisoning Prevention Program (CLPPP) was established in 1991, as a result of the California legislature mandating the California Department of Health Services (CDHS) to develop and enact a standard of care for identifying and managing children with elevated blood lead levels. CLPPP, funded by the CDHS, is structurally placed under two Programs within Department of Public Health. The team of public health nurses, health educators, and epidemiology staff is under Maternal, Child, and Adolescent Health Programs; and the team of registered environmental health specialists is under Environmental Health. The two teams work closely together to ensure nursing and environmental case management and follow-up for lead-burdened children; to promote screening; and to carry out primary prevention, targeted outreach and education, and surveillance activities.
Although gasoline and paint are no longer made with lead in them, lead is still a health problem. Lead is everywhere, including dirt, dust, new toys, and old house paint. Unfortunately, you cannot see, taste, or smell lead.
Lead is found in:
- House paint before 1978. Even if the paint is not peeling, it can be a problem. Lead paint is very dangerous when it is being stripped or sanded. These actions release fine lead dust into the air. Infants and children living in pre-1960’s housing (when paint often contained lead) have the highest risk of lead poisoning. Small children often swallow paint chips or dust from lead-based paint.
- Toys and furniture painted before 1976.
- Painted toys and decorations made outside the U.S.
- Lead bullets, fishing sinkers, curtain weights.
- Plumbing, pipes, and faucets. Lead can be found in drinking water in homes containing pipes that were connected with lead solder. Although new building codes require lead-free solder, lead is still found in some modern faucets.
- Soil contaminated by decades of car exhaust or years of house paint scrapings. Lead is more common in soil near highways and houses.
- Hobbies involving soldering, stained glass, jewelry making, pottery glazing, and miniature lead figures (always look at labels).
- Children’s paint sets and art supplies (always look at labels).
- Pewter pitchers and dinnerware.
- Storage batteries.
Children get lead in their bodies when they put lead objects in their mouths, especially if they swallow the lead object. They can also get lead poison on their fingers from touching a dusty or peeling lead object, and then putting their fingers in their mouths or eating food afterward. Children also can breathe in tiny amounts of lead.