This is the fourth blog in a series focused on important tools that people can use to quantify the societal benefits of reducing lead exposure. To find the series, click on “Societal Benefits” in the Categories menu to the right.
What Happened
In support of its October 2024 rulemakings1 that tightened standards for lead in drinking water and lead in interior dust, EPA finalized its formula to quantify the number of avoided attention deficit hyperactive disorders (ADHD) cases. To estimate the societal benefits, the value of each ADHD case is between $128,559 and $184,149 based on how many cases persist into adulthood and age of diagnosis (6 versus 11 years).
As an example, a 10% reduction in the median blood lead level of children aged 6 to 11 years would reduce diagnosed ADHD cases between 7,410 and 18,809 per year nationally for societal benefits of $953 million to $3.46 billion per year.2 For context, the estimated ADHD-related societal benefits for EPA’s Lead and Copper Rule Improvements were $196 million to $600 million per year and its Dust Lead Standard and $129 million to $274 million per year.
Unleaded Kids has developed an Excel Spreadsheet to help those wanting to make their own calculations. See end of blog for details.
Why it Matters
Almost one in ten children are diagnosed with ADHD.3 It is neurodevelopmental disorder characterized by persistent symptoms of hyperactivity, impulsivity, or inattention. Inattentive symptoms include difficulty in sustaining concentration, keeping organized, and completing tasks. Hyperactivity and impulsivity refer to symptoms such as restlessness, excessive talking, and interrupting others.
ADHD disrupts both the child’s development and impacts their family. Families of children with ADHD have increased healthcare, education, and productivity costs. The ADHD symptoms persist into adulthood for between 30% and 90% of children. Based on research by Doshi et al. in 2012, EPA estimates the present value of avoiding ADHD cases range from $128,559 to $184,149 based on how many cases continue into adulthood.4
Lead exposure is one of many factors that contribute to ADHD. In its 2013 Integrated Science Assessment (ISA) for Lead, EPA first concluded there was a causal relationship between lead exposure and inattention, impulsivity, and hyperactivity in children. In its 2024 ISA, EPA reaffirmed that finding. A key study found that children in the top one-third of blood lead levels are 2.3 times more likely to be diagnosed with ADHD than those in the lowest third.
Our Take
Thanks to EPA’s efforts to quantify the relationship between ADHD cases and blood lead levels, the public has a valuable tool to make more informed decisions about reducing children’s exposure to lead, especially those aged 6 to 11.
Fortunately, researchers such as Frohlich, Ji, and many others have invested much of their careers in gathering data, developing those statistical tools, and refining the analysis based on feedback and peer review. After the researchers published the studies in the peer review literature, EPA rigorously:
- Reviewed all available studies that could be used to develop quantitative relationships between changes in lead exposure and/or changes in blood lead levels and changes in health endpoints.
- Evaluated the studies for quality and potential biases.
- Developed a separate report for each health endpoint. In addition to the study quality review findings, each report provides quantitative estimates, based on health impact functions derived from the identified relationships between blood lead and adverse health effects which allow researchers to quantify the potential changes in the health endpoint due to an intervention.
- Had the reports for quantified health endpoints reviewed by EPA experts.
- Successfully completed inter-agency review through White House’s Office of Management and Budget.
There are several issues with the estimates that need to be resolved on external peer review including impacts as the blood lead levels get closer to zero and what qualifies as a diagnosis of ADHD. Nonetheless, there is sufficient information to quantify the societal benefits of reducing lead exposure for use in federal rulemaking.
Details on Estimating the Calculating
the Number of Avoided ADHD Cases
Unleaded Kids reviewed Section 5.5.3 and 5.5.4 of EPA’s Economic Analysis for its Lead and Copper Rule Improvements and developed an Excel Spreadsheet to help those wanting to make their own calculations. The instructions are in the spreadsheet. Click here for a PDF of the worksheet. Click here for the key pages from EPA’s economic analysis explaining the formula.
To estimate the change in ADHD cases for a given change in blood lead levels, EPA used the following equation with 9.6% representing the baseline rate of ADHD.
To calculate the societal benefits of those cases avoided, EPA used the values in Exhibit 5-26.
- Lead and Copper Rule Improvements and Dust-Lead Hazard Standards. ↩︎
- 10% for children 6 to 11 years of age at geometric mean – 0.475 µg/dL based on NHANES biomonitoring conducted in 2017–18. See https://archive.cdc.gov/www_cdc_gov/exposurereport/blood_lead_early_release.html. ↩︎
- See Exhibit 6 for range of estimates in Abt Associates’ “Developing a Concentration-Response Function Relating Childhood Lead Exposures and ADHD” report to EPA in December 2022. ↩︎
- See Exhibit 5-26 in Section 5.5.4 of EPA’s Economic Analysis for the Lead and Copper Rule Improvements. ↩︎