What is the US prevalence of lead toxicity?

Updated: Jan 16, 2020
  • Author: Pranay Kathuria, MD, FACP, FASN, FNKF; Chief Editor: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS  more...
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Children are more likely than adults to have elevated blood lead levels (BLLs). More hand-to-mouth behavior and better gastrointestinal absorption of lead are some factors contributing to higher BLLs in children. In fact, lead poisoning is said to be the most common environmental illness of children in the United States. The incidence varies with age, socioeconomic status, the population of a given community, race, and the age of the home.

No blood level of lead is safe. In 1991, the CDC defined BLLs of ≥10 µg/dL as the "level of concern" for children aged 1–5 years. However, in May 2012, the CDC accepted the recommendations of its Advisory Committee on Childhood Lead Poisoning Prevention that the term "level of concern" be replaced with an upper reference interval value defined as the 97.5th percentile of BLLs in US children aged 1–5 years from two consecutive cycles of NHANES (National Health and Nutritional Examination Survey). The current upper reference interval value of the 97.5th percentile of the distribution of the combined 2007–2008 and 2009–2010 cycles of NHANES was calculated as 5 µg/dL. [15]

There has been a remarkable decline in BLLs in children over the past 30 years. Data from the 1976–1980 cycle of NHANES indicated that an estimated 88% of children aged 1–5 years had BLLs ≥10 µg/dL. Since then, the percentage has fallen sharply, to 4.4% during 1991–1994 (NHANES III), to 1.6% during 1999–2002, and to 0.8% during 2007–2010. [16] The percentage of children aged 1–5 years with BLLs ≥5 µg/dL from the 2007–2010 NHANES cycle was 2.6% or approximately 535,000 US children. Despite progress in reducing BLLs among children in this age group overall, long-standing disparities persist. The geometric mean BLLs (GM BLLs) among younger children, those belonging to poor families, and those enrolled in Medicaid were significantly higher compared with their older, more affluent counterparts, while the GM BLLs for non-Hispanic black children were significantly higher compared with either non-Hispanic white or Mexican American children.

Generally, adults develop lead poisoning as the result of an occupational exposure or from exposure through a hobby.

Adult Blood Lead Epidemiology and Surveillance (ABLES) is a program that works with states to accurately measure trends in work-related adult BLLs, to better target interventions and prevent lead exposures. The National Institute for Occupational Safety and Health (NIOSH) in 2015 designated 5 µg/dl of whole blood, in a venous blood sample, as the reference BLL for adults. A BLL ≥5 µg/dL is considered abnormal. The US Occupational Safety and Health Administration (OSHA) Lead Standards require workers to be removed from lead exposure when BLLs are equal or greater than 50 µg/dL (construction industry) or 60 µg/dL (general industry) and allow workers to return to work when the BLL is less than 40 µg/dL.

Data from the NHANES show that the average BLL (geometric mean) of all adults in the United States in 2009–2010 was 1.2 µg/dL. Over the last 18 years, a 54% decrease in the national prevalence rates of BLL ≥25 μg/dL has been documented using ABLES surveillance data. In 1994, the rate was 14.0 employed adults per 100,000; in 2011, the rate was reduced to 6.4. In 2010, 40 state ABLES programs that provided data reported 31,081 adults with BLLs ≥10 μg/dL. Among these, 8,793 had BLLs ≥25 μg/dL, and 1,388 had BLLs ≥40 μg/dL. Overall, the national prevalence rate of BLLs ≥10 μg/dL declined from 26.6 adults per 100,000 employed in 2010 (among 37 states) to 20.4 in 2013 (among 29 reporting states). [17]

The highest numbers of workers exposed to lead with BLLs of 25 µg/dL or greater included employees in the storage battery manufacturing and lead and zinc ore mining industries, according to the ABLES report. [18]

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