Majority of Obese Teens Were Also Obese in Adolescence, Study Says

A new study led by researchers at Boston Children’s Hospital looked at childhood obesity patterns over time and found that earlier interventions are needed when it comes to teen weight loss.

The study highlights several possible contributing factors to the risk of obesity including: watching a lot of television; having an obese parent; having lower household education; and having a negative body image.

Furthermore, children who are overweight or obese by fifth grade, the researchers found, have a higher risk of becoming or remaining obese in their teen years. This research was recently published in the journal Pediatrics.

“We know from prior studies that obesity in children is correlated with their likelihood of being obese when they are older,” says study lead author Mark Schuster, MD, PhD, chief of the Division of General Pediatrics at Boston Children’s and a professor at Harvard Medical School. “But the pattern of change over time, of entry to and exit from obesity, hasn’t generally been studied.”

Additional risk factors reviewed in the study included race, education, fast food and soda consumption, and activity level.

“Not a lot of children become newly obese in adolescence,” Schuster says. “If a child is already obese in fifth grade, she is likely to remain obese, and most children who are obese in tenth grade were already obese before adolescence. We cannot depend on the idea that a child will ‘grow out of it’ as they get older.”

Schuster and his team looked at data from approximately 4,000 randomly selected fifth-grade public school children between 2004 and 2006 in three metropolitan areas: Birmingham, Alabama; Houston, Texas; and Los Angeles County, California.

Then, the researchers re-contacted the children and their families five years later—when most of the children were in tenth grade—to collect additional and updated data on things like body mass index and current daily habits. This new information was then analyzed to see whether the child was newly obese or remained that way over time.

“We studied these children before most had entered adolescence and then again when they were in the middle of their teens,” Schuster explained. “This allowed us to avoid confounding changes related to the onset of puberty.”

According to the study:

• 65 percent of obese fifth-graders remained obese in tenth grade; 23 percent were no longer obese but were still overweight; only 12 percent became normal weight.
• 83 percent of obese tenth-graders had been obese in fifth grade.
• 87 percent of normal-weight fifth-graders remained at normal weight in tenth grade.
• Obese fifth-graders had a 37 percent chance of losing weight to become overweight if they did not perceive themselves as much heavier than ideal, but only a 26 percent chance if they did.
• Obese fifth-graders had a 43 percent chance of transitioning to overweight status if they came from households with a college graduate, but only a 33 percent chance if they came from households without a college graduate.
• Overweight fifth-graders had a 21 percent chance of being obese in tenth grade if they watched 30 hours of TV per week and had an obese parent.
• Those who watched 10 hours per week and had an obese parent had a 6 percent chance.

Schuster says that this study shows a great need for doctors and families to address obesity issues when a child is still young, before they reach the teen years.

“We as clinicians need to do more to educate families and encourage them to have healthier foods at home and especially when they eat outside the home. We also need to encourage them to increase exercise and reduce screen time,” Schuster says. “There are also many things we can work towards with schools, such as removing sugar-sweetened beverages, getting physical education back as a priority and improving school meals.”