The CDC (Centers for Disease Control and Prevention) emphasized that "no safe blood lead level in children has been identified". Lead exposure in children can lead to both cognitive and behavioral problems.
Lead poisoning, also known as sturnism, colica Pictonum, Devon colic, painter's colic and plumbism is a medical condition caused by high BLLs (blood lead levels). Lead undermines a range of body processes and can damage many organs and tissues, including the nervous system, reproductive system, intestines, bones, kidneys, and heart.
High BLL is particularly damaging to children, because it interferes with the development of the nervous system, and can be the cause of lifelong learning and behavior disorders.
Signs and symptoms of lead poisoning include:
- Abdominal pain
- Behavioral problems
- Learning disabilities
- Loss of appetite
- Developmental delays - such as talking and use of words
- In severe cases, there may be kidney failure, seizures, coma and even death
The authors of this latest report estimated how many children aged 1 to 5 years in the USA were at risk of adverse health effects from lead exposure by analyzing data from NHANES (the National Health and Nutrition Examination Survey) from two periods - 1999-2002 and 2007-2010.
The authors found that according to the 2007-2010 data, 2.6% of US kids aged 1 to 5 had BLLS of at least 5 µg/dL, the upper reference interval value. This translates to approximately 535,000 children in the USA from 1 to 5 years of age with BBLs of 5 µg/dL or more.
In a previous study in August 2007, the CDC estimated that about 310,000 kids under five had BLLs exceeding 10 µg/dL.
In 1991, the CDC's "threshold of concern" for kids aged 1 to 5 was ≥10 µg/dL - this was reduced to ≥5 µg/dL in May 2012 after the CDC's Advisory Committee on Childhood Lead Poisoning Prevention recommendation, the level equal to the 97.5th percentile of the full spectrum of childhood BLLs.
A great deal of work needs to be done to achieve the Healthy People 2020 target of reducing mean BLLs for all American children, despite progress in bringing down BLLs among very young children.
According to lead author, Mary Jean Brown, ScD. and team, mean BLL in young kids dropped by about one-third over a ten-year period. In the 1999-2002 period, the mean BLL was 1.9 µg/dL, compared to 1.3 µg/dL during 2007-2010.
Both BLL figures were much lower than in 1976-1980, when 88% of children had BLLs of at least 10 µg/dL (and a mean of 15 µg/dL).
Dr. Brown said:
"Substantial progress has been made over the past 4 decades in reducing the number of children with elevated blood lead levels. These reductions reflect the impact of strategies coordinated and implemented at national, state, and local levels.
They include elimination of lead in vehicle emissions, elimination of lead paint hazards in housing, reduction in lead concentrations in air, water, and consumer products marketed to children, and identification and increased screening of populations at high risk."
Non-Hispanic black children showed averages of 1.8 µg/dL in 2007-2010, compared to 1.3 µg/dL in non-Hispanic white and Mexican-American children. (Non-Hispanic black children had the highest averages thirty-five years ago as well).
In the past, when lead-based paints were more common, BLLs among children from low income households built before 1950 were higher.
Lead exposure can have lifelong consequencesThe authors explained that even at fairly low levels, lead exposure can have consequences that can affect children for the rest of their lives. More needs to be done to address the persistent disparity in BLLs among children of different ethnicities and races.
According to the Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP), these disparities in BLLs can be traced to differences in:
- Environmental conditions
- Housing quality
- Other factors designed to control/eliminate lead exposure
For effective prevention, children's environmental exposures to water, paint, dust and soil must be reduced. Awareness of lead hazards must be improved, as well as nutritional interventions to increase calcium and iron, which can reduce the body's absorption of lead.
The authors added "Given the continued disparity in BLLs, resources should be targeted to those areas where children are most at risk. NHANES provides useful data for measuring progress towards eliminating high BLLs and ensuring that resources are targeted toward the most vulnerable children."
Researchers from Occupational Knowledge International (OK International) reported in the Journal of Occupational and Environmental Hygiene that children in developing nations who live near lead battery manufacturing and recycling operations had 13 times more lead in the their blood compared to American children.