Rook, lood en ADHD*
Uit een Amerikaanse studie onder ruim 2.500 kinderen in de leeftijd van 8-15 jaar blijkt dat zowel blootstelling aan sigarettenrook als aan lood de kans op ADHD flink doet toenemen. Kinderen die blootgesteld worden aan rook hebben wel 2,4 keer meer kans op ADHD, zij die blootgesteld worden aan lood 2,3 keer meer kans. Lood ondanks dat het al zo lang niet meer gebruikt wordt het nog steeds aangetroffen in het milieu zoals in oude huizen en de bodem. Oude huizen als gevolg van oude verf die lood bevat en de bodem vaak als gevolg van de loodhoudende benzine. De overheid beschouwt lood pas gevaarlijk bij bloedwaarden van 10 mcg/dl en hoger. In deze studie hadden de kinderen die bloot gesteld waren aan lood veel lagere bloedwaarden dan de 10 mcg/dl. Kinderen die zowel aan rook als lood blootgesteld waren hadden wel 8,1 keer meer kans op het krijgen van ADHD. Kinderen die niet blootgesteld worden aan sigarettenrook en lood hebben daardoor 35% minder kans op het krijgen van ADHD.
Lead, smoke exposure in kids linked to ADHD
Eliminating contact could reduce cases a third, study finds
Eliminating childhood exposure to lead and tobacco smoke could cut the incidence of ADHD in the U.S. by more than a third, according to new research from Cincinnati Children's Hospital Medical Center.
Individually, each substance increases a child's risk of developing attention deficit/hyperactivity disorder, but children exposed to both environmental toxins are more than eight times more likely to develop ADHD than children who weren't exposed to either substance, the study found.
"Tobacco and lead exposure together seem to have a synergistic, negative effect," said Tanya Froehlich, a physician in the division of developmental and behavioral pediatrics at Cincinnati Children's, and lead author of the study.
Her research, which she will present today at the annual meeting of the Society for Developmental and Behavioral Pediatrics at the Hyatt Regency Cincinnati downtown, found ADHD could be reduced 35 percent by eliminating exposure to the toxins.
That's more than 800,000 of the 2.4 million children ages 8 to 15 known to have the disorder, Froehlich said.
She and her colleagues found that children exposed prenatally to tobacco smoke were 2.4 times more likely to develop ADHD than children who weren't exposed.
Childhood exposure to lead also increases the risk of ADHD, Froehlich said. Her research found children with the highest levels of lead exposure were 2.3 times more likely to develop ADHD.
Federal guidelines call for treatment if children have blood lead levels higher than 10 micrograms per deciliter, but the lead-exposed children Froehlich studied had blood lead levels well below that.
The study is one of the first to quantify the risks of lead and tobacco smoke exposure and ADHD.
Children exposed to both tobacco smoke and lead were 8.1 times more likely to develop ADHD than children who weren't exposed to either toxin, the study found.
"If children are exposed to both lead and prenatal tobacco, it's not like being exposed individually," Froehlich said. "It's considerably worse."
The study is based on data gathered from 2,588 children ages 8 to 15 in the National Health and Nutrition Examination Survey from the National Center for Health Statistic at the Centers for Disease Control and Prevention. The survey is a nationally representative sample of the U.S. population, designed to collect information about Americans' health and diet.
Previous studies have shown that both lead and tobacco smoke interfere with the function of dopamine, a chemical that helps transmit nerve signals in the brain.
Froehlich said her study highlights the need to ratchet up public health efforts to protect children from lead and secondhand
smoke. (December
2008)
