A.D.H.D. is attention deficit hyperactivity disorder. Government estimates say three to seven percent of school-age children in the United States have it. Adults can also have it. People with A.D.H.D. have problems with paying attention, controlling their behavior and being overly active.
Now, a study has linked an increased risk of A.D.H.D. in children to exposure to some kinds of pesticides. The chemicals are known as organophosphate pesticides. They kill insects by attacking their nervous systems. Earlier studies have shown that some of the compounds cause hyperactivity and thinking deficits in laboratory animals.Researchers at the University of Montreal in Canada and Harvard University in Massachusetts did the study.
It involved more than one thousand one hundred children between the ages of eight and fifteen. One hundred nineteen of them were identified as having A.D.H.D.The researchers tested all the children for products that break down from organophosphates. Maryse Bouchard of the University of Montreal and Harvard led the research team. She said: “The higher the level of pesticide residue in the urine, the higher the risk of A.D.H.D. in the children.”The scientists reported that the risk of the disorder was almost double in children with high levels compared to those with no measurable level.
They say exposure at levels common among children in the United States may increase the chances that a child will be diagnosed with A.D.H.D. Maryse Bouchard says the study found that exposure could play a part in behaviors such as inattention and hyperactivity. But she also says the study does not prove that the chemicals cause the disorder. The researchers say forty organophosphate pesticides are registered with the United States government. The chemicals are used to protect fruits and vegetables.
They are also used to poison insects in other places such as homes. Lynn Goldman is an environmental health scientist at Johns Hopkins University School of Public Health in Maryland. She notes that the use of pesticides, including organophosphates, is widespread in developing countries. Children come in contact with high levels of pesticides through farming.The study was published in the journal Pediatrics. And that’s the VOA Special English Health Report.
Words in This Story
deficit – n. the total amount by which money spent is more than money received
hyperactivity – n. (of a person) the state of having more energy than is normal, becoming excited easily, and being unable to stay still or think about work
disorder – n. a state of untidiness or lack of organization
behavior – n. the way that a person, an animal, a substance, etc. behaves in a particular situation or under particular conditions
pesticide – n. a chemical substance used to kill harmful insects, small animals, wild plants, and other unwanted organisms
organophosphate – n. a chemical used for killing insects and small animals that damage crops
compound – n. a chemical that combines two or more elements
residue – n. the part that is left after the main part has gone or been taken away, or a substance that remains after a chemical process such as evaporation
exposure – n. the fact of experiencing something or being affected by it because of being in a particular situation or place
widespread – adj. existing or happening in many places and/or among many people
paediatrics – n. (US pediatrics)the science or study of medical care for children
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