"A number of studies have demonstrated negative effects of heavy television viewing. However, timing of exposure is an important consideration as reducing viewing to acceptable levels can reduce the risk of behavioral and social problems," said Kamila Mistry, MPH, lead author of the study and a doctoral candidate in the Bloomberg School's Department of Population, Family and Reproductive Health.
For the study, the research team analyzed data for 2,707 children collected from the Healthy Steps for Young Children national evaluation. Parents were surveyed about their child's television viewing habits and behavior at 2.5 and at 5.5 years of age.
Sixteen percent of parents reported that their children watched two hours or more of television daily at 2.5 years of age (early exposure), while 15 percent reported that their children watched two hours or more of television daily at 5.5 years of age (concurrent exposure). One in five parents reported that their children watched two hours or more of television daily at both 2.5 years and at 5.5 years of age (sustained exposure). Sustained exposure to television was associated with behavioral problems. However, early exposure that was subsequently reduced was not a risk for behavior problems. Concurrent viewing was associated with fewer social skills, while sustained and early viewing had less of an impact on social skill development.
The study also found that having a television in the child's bedroom at 5.5 years of age was associated with behavioral problems, poor social skills and poor sleep. Forty-one percent of the children included in the study had a television in his or her bedroom.
"Children who reduced their viewing by 5.5 years of age were not at greater risk for behavior and social problems," said Cynthia Minkovitz, MD, MPP, senior author of the study and associate professor with the School's Department of Population, Family and Reproductive Health. "It is vital for clinicians to emphasize the importance of reducing television viewing in early childhood among those children with early use."