Childhood lead exposure quadruples ADHD risk.
Braun et al. (2006) published the dose-response curve in Environmental Health Perspectives. NHANES quintile analysis confirms it. Lead in the top blood-lead quintile is associated with a 4.1x increase in ADHD prevalence over the bottom quintile.
01
What the data shows.
NHANES blood-lead in 4-15-year-olds, segmented into quintiles, correlated with parent-reported ADHD diagnosis. The relationship is monotonic and dose-responsive. There is no apparent safe lower bound. The bottom quintile still shows elevated risk versus the cleanest 5% of children.
Dose-response, not threshold.
The historical framing was "below the action level is safe." The data does not support that. Every increment of blood lead adds to the ADHD risk on a smooth curve.
02
What that means for a parent.
1
A blood test is a snapshot.
It tells you what is circulating today. It does not tell you what is in the bones, and it does not tell you the average over the past year.
2
The home test is upstream.
Find the source. Remove the dose. The blood result follows in 1-2 months.
3
Calcium, iron, and vitamin D sufficiency matter.
All three compete with lead at the gut absorption step. A well-fed kid absorbs less of the dose that does land in their mouth.