foodconsumer.org: ADHD risks increase in children exposed to lead and cigarette smoke

ADHD risks increase in children exposed to lead and cigarette smoke
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admin on 11/24/2009 22:57:00
 
By Sheilah Downey
Children exposed to lead and tobacco smoke face an eight times higher risk of
developing ADHD than unexposed children, a new study finds.
Researchers found that children exposed to tobacco smoke in the womb are more
than twice as likely (2.4) to have ADHD than children who were not exposed.
Those with blood lead levels in the top third were 2.3 times more likely to have
ADHD.
The study from Cincinnati Children's Hospital Medical Center estimated that by
eliminating these two environmental risk factors, up to 35 percent of ADHD cases
in children could be reduced, changes that could affect about 800,000 children,
according to the study.
"Tobacco and lead exposure each have their own important adverse effect," says
lead author Dr. Tanya Froehlich, of the Hospital's Division of Developmental and
Behavioral Pediatrics. "But if children are exposed to both lead and prenatal
tobacco the combined effect is synergistic."
Lead is a known neurotoxin that can affect children's learning disabilities and
increase risk of behavioral problems. In a study published earlier this year,
Froehlich and colleagues found that approximately 2.4 million children between
the ages of 8 and 15 have ADHD, but that an estimated 1.2 million of them
haven't been diagnosed or treated.
By defining the risk factors for ADHD, researchers say it may point to a way to
prevent more cases of the disability.
"Although we tend to focus on ADHD treatment rather than prevention, our study
suggests that reducing exposures to environmental toxicants might be an
important way to lower rates of ADHD," said senior author Dr. Robert Kahn.
The study was based on data of 8 to 15 year olds from the National Health and
Nutrition Examination Survey (NHANES) which was taken between 2001 and 2004
Prenatal tobacco exposure was measured by reports from maternal cigarette use
during pregnancy. Lead levels were assessed using current blood lead levels.
Approximately 8.7 percent of the children in the study met criteria for ADHD.
Researchers said the lead levels of children in the study were well below the
action levels set by the Centers for Disease Control which are 10 micrograms per
deciliter.
Lead levels have been a problem in children's toys, a situation the Consumers
Product Safety Commission (CPSC) has closely monitored. In 2007, the CSPC
announced that Fisher Price toy manufacturer was voluntarily recalling a number
of toys that were found to have unsafe levels of lead. The toys were made in
China.