Number of Children With Elevated Blood Lead Levels Probably Underestimated: Study

New research suggests that many children throughout the United States may have elevated lead levels that could be impacting their health and development, but are never being properly tested or diagnosed. 

In a study published last month in the medical journal Pediatrics, researchers with the California Environmental Health Tracking Program at the Public Health Institute estimate that only half of all cases of children five and under with elevated lead blood levels (EBLLs) are being reported to the U.S. Centers for Disease Control and Prevention (CDC), which suggests that the nation has grossly underestimated the number of children likely negatively affected by lead poisoning.

Elevated blood lead levels are an indicator that children may be at risk for side effects of lead poisoning, which can cause serious nervous system injury, brain damage, seizures, growth or mental disability, as well as other severe health problems throughout the rest of their childhood and life.

Researchers looked at data from every state, comparing estimates and case reports, as well as data from the National Health and Nutrition Examination Survey from 1999 to 2010, involving children one to five years old. Despite laws requiring testing, the findings indicate that many children do not get tested, and in fact, the majority of children who qualify for Medicaid do not get tested.

“Approximately 1.2 million cases of EBLL are believed to have occurred in this period, but 607,000 (50%) were reported to the CDC,” the researchers found. “Including only states and years for which reporting was complete, the reporting rate was 64%. pediatric care providers in 23 of 39 reporting states identified fewer than half of their children with EBLL.”

The study also discovered that while most of the reported cases came from the Northeast and Midwest, they estimate that the greatest number of children with elevated lead levels are likely in the South. The researchers estimate that children in the southern and western states likely have three times as many children with elevated lead levels in their blood than have been reported.

“Based on the best available estimates, undertesting of blood lead levels by pediatric care providers appears to be endemic in many states,” they concluded.

The rates may now be even higher. At the time of the study, the threshold set by the CDC for EBLLs in children was 10 micrograms per deciliter. However, in 2012, the CDC dropped the “level of concern” for blood lead levels in children under the age of 6 from 10 micrograms per deciliter to 5. The move doubled the amount of children in the U.S. considered at risk for adverse health effects at the time.

The agency reviews its standards for elevated lead levels in children every four years. However, it only applies to children under the age of 6, as there is no lead threshold for older children and adults.The CDC is now considering reducing lead levels of concern yet again, from 5 micrograms per deciliter to 3.5 micrograms per deciliter.

One of the more common causes of of lead poisoning is lead-based paint, which was banned in the United States in 1978 due to the risk of severe and permanent brain damage and developmental problems, particularly in children. However, a number of older homes still contain the toxic paint on the walls, and if it flakes or peals off, young children could ingest the paint chips or breathe dust that comes from the paint, resulting in lead poisoning.

The majority of those children are poor and live in older urban areas, mainly in the inner city. Most are minorities, meaning such exposures add to numerous problems already plaguing inner city black and Latino youths, such as poverty, high crime and poor schools.

Recent years have also seen a focus on lead in drinking water, stemming from the recent and ongoing Flint water crisis, during which a change to the water system in the Michigan city resulted in high levels of lead in residents’ drinking water, causing thousands of children to suffer lead exposure and, potentially, lead poisoning.