Lead May Be the Culprit in ADHD

[n2doc]

ScienceDaily (Jan. 29, 2010) — ADHD, or attention-deficit/hyperactivity disorder, is among the costliest of behavioral disorders. Its combination of inattention, impulsivity and hyperactivity leads to accidental injuries, school failure, substance abuse, antisocial behavior and more. Yet despite nearly a century of study, the disorder’s roots remain mysterious.

Much of modern ADHD research has focused on heritability of the condition, and indeed evidence suggests that genes may account for as much as 70 percent of hyperactivity and inattention in children. But that leaves 30 percent unexplained, so recently the focus has shifted to the environment. What is it that triggers an underlying susceptibility and changes it into a full-blown disorder? New research suggests that the culprit may be an old villain—lead—and what’s more it explains the causal pathway from exposure to disability.

Lead is a neurotoxin. This has been known for a long time, and in fact government regulation drastically reduced environmental lead a generation ago. But regulating automobile fuel and paint didn’t entirely eliminate lead from the environment. It’s found in trace amounts in everything from children’s costume jewelry to imported candies to soil and drinking water. Every American today is exposed to low levels of the metal, and indeed nearly all children have measureable levels of lead in their bodies. According to psychological scientist Joel Nigg of the Oregon Health & Science University, this universal low-level exposure makes lead an ideal candidate for the disorder’s trigger.

This was just a theory until quite recently, but two recent studies now provide strong evidence. The first study compared children formally diagnosed with ADHD to controls, and found that the children with the disorder had slightly higher levels of lead in their blood. This study showed a link only between blood lead and hyperactivity/impulsivity symptoms, not inattention. But a second study showed a robust link between blood lead and both parent and teacher ratings of ADHD symptoms, including both hyperactivity and attention problems. In both studies, the connection was independent of IQ, family income, race, or maternal smoking during pregnancy.

more:

http://www.sciencedaily.com/releases/2010/01/100128130227.htm

[HysteryDiagnosis]

1. Look at the date on this paper.... the wheels of medical science

turn slowly too.



Arch Environ Health. 1996 May-Jun;51(3):214-20.
Hair lead levels related to children's classroom attention-deficit behavior.

Tuthill RW.

School of Public Health, University of Massachusetts, Amherst, USA.

The goal of this study was to evaluate the relationship between hair lead levels of children and their attention-deficit behaviors in the classroom. Scalp hair specimens were obtained from 277 first-grade pupils, teachers completed the abbreviated Boston Teacher's Rating Scale for rating classroom attention-deficit behavior, and parents completed a short questionnaire. The children's hair lead concentrations ranged from less than 1 to 11.3 ppm (microg/g). The striking dose-response relationship between levels of lead and negative teacher ratings remained significant after controlling for age, ethnicity, gender, and socioeconomic status. An even stronger relationship existed between physician-diagnosed attention-deficit hyperactivity disorder and hair lead in the same children. There was no apparent 'safe' threshold for lead. Scalp hair should be considered a useful clinical and epidemiologic approach for the measurement of chronic low-level lead exposure in children.