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Physical Activity and Screen Time Levels May Predict Risk of Obesity in Children
Obesity at any age increases the risk for several serious illnesses, conditions, and even early death. It contributes to diseases and conditions like diabetes, heart disease , high blood pressure , and bone and joint problems. When obesity exists in childhood, it significantly increases the child's chance of developing one of these serious conditions much earlier in life. In fact, as the rate of childhood obesity has risen, so has the rate of type 2 diabetes in children. This type of diabetes was formerly known as adult onset since it was so rare for children to develop it. As with adults, most children gain weight because of an excess of food, particularly junk food, and too little physical activity.
Researchers from Iowa State University examined how significantly the combination of low physical activity levels and time in front of a TV (screen time) affected the chances of a child being overweight. The study, published in the Journal of Pediatrics , found that children with lower levels of physical activity and higher amounts of screen time were 3-4 times more likely to be overweight.
About the Study
The study was a cross sectional observational study based on data collected from 709 children aged 7-12 years. All of the children had their height and weight measured and their BMI calculated by trained staff. A survey was also sent to all the students to determine daily screen time, and the children wore pedometers over a seven-day period to establish physical activity levels.
The physical activity and screen time guidelines from the American Academy of Pediatrics (AAP) were used as a reference. Ideal screen time was no more than two hours per day; physical activity goal was between 11,000-13,000 pedometer steps. The study found that:
- Overall, 24% of the boys and 30% of the girls were overweight (or obese).
- Fewer than 50% of the children met the pedometer-related physical activity levels.
- Only 27% of boys and 35% of girls met the screen time guidelines (fewer than two hours of screen time per day).
- Boys that didn't meet either requirement were at least four times as likely to be overweight than boys that met both requirements.
- Girls that didn't meet either requirement were at least three times as likely to be overweight than girls that met both requirements.
How Does This Affect you?
In an observational study, researchers do not control any of the factors that can influence the outcome. There are steps taken in the calculation of results to account for all relevant factors, but it is not always possible. As a result, this type of study cannot prove a cause and effect relationship, but it does indicate a connection. Lack of physical activity and increased screen time may significantly increase your child's risk of being overweight.
It is important to monitor the amount of time your child spends in front of a TV, computer, or with a video game. They should be spending fewer than two hours a day in front of a screen. Encourage physical activity, whether it is walking or biking instead of car rides or joining a physically active group (sport team, dancing, hiking). It is also important that you set a good example by making family time active. Take a walk together after dinner, go for family hikes, or try to walk to destinations rather than driving a car. Helping your child adopt healthy habits early in life may not only keep them healthy as children but may also make them more likely to continue healthy habits into their adult years.
American Academy of Pediatrics
Laurson KR, Eisenmann JC, Welk GJ, Wickel EE, Gentile Da, Walsh DA. Combined influence of physical activity and screen time recommendations on childhood overweight. J Pediatr . 2008 Aug;153(2):209-14.
- Reviewer: Brian Randall, MD