CHICAGO (Reuters) - The more television children watch between the ages of 1 and 3, the greater their risk of having attention problems at age 7, U.S. researchers reported on Monday.
They found that each
hour of television that preschoolers watched per day increased the
risk of attention problems such as attention deficit-hyperactivity
disorder by almost 10 percent later on.The study, published in the April issue of Pediatrics, the journal of the American Academy of Pediatrics, adds inattention to the list of harmful effects of excessive television viewing that also includes obesity and violent behavior.
Frederick Zimmerman of the University of Washington in Seattle, one of the authors, said it was impossible to say what a "safe" level of TV viewing would be for children between the ages of 1 and 3.
"Each hour has an additional risk," he said in an interview. "You might say there's no safe level since there's a small but increased risk" with each hour.
"Things are a trade-off. Some parents might want to take that risk. We didn't find a safe level in that sense."
The data from 2,500 children covered by the study found that they watched an average of 2.2 hours per day at age 1 and 3.6 hours per day at age 3. But some watched 12 hours or more.
The ages are significant because brain development continues through those years, the study said.
"This study suggests that there is a significant and important association between early exposure to television and subsequent attentional problems," said Dimitri Christakis, a physician at Children's Hospital and Regional Medical Center in Seattle who headed the study.
"We know from national estimates that children watch an average of two to three hours of television a day in the 1- to 3-year-old age group, and that as many as 30 percent of all children have a television in their bedroom," he said.
"There is a tremendous and growing reliance on television for a variety of reasons. However parents should be advised to limit their young child's television viewing," Christakis said.
In the United States between 3 percent and 5 percent of children are diagnosed with attention deficit disorder, which is marked by reduced ability to concentrate, difficulty in organizing and impulsive behavior. The symptoms do not typically show up until children are older, around age 7.
STUDY LIMITED
The authors said the study had some limitations.
The television viewing data came from the parents and may not be completely accurate. Also, there is no way to know whether the children already had attention problems early on that attracted them to TV viewing, though symptoms don't appear that early, it said.
It was also possible the parents who allowed excessive TV viewing were themselves distracted and neglectful, creating a household that fostered attention problems in the children. Attention deficit-hyperactivity disorder has a high heritability level, the study said.
And the study did not look at what kinds of programs the children watched.
"Despite these limitations our results have some important implications if replicated in future studies," it said. "First we (have) added inattention to the previously studied deleterious consequences of excessive television viewing ... (and) our findings suggested that preventive action can be taken."