Smartphone ownership by age 12 linked to higher eating disorder symptoms in teens

Kids who have smartphones by the age of 12 may be more likely to report eating disorder symptoms two years later, according to a new study.

Nearly a quarter of nearly 9,000 U.S. adolescents who had a smartphone at that age reported at least one symptom by age 14, such as binge eating, disrupted sleep, or tying self-worth to weight.

But fewer than 16 percent of those who don’t have smartphones at age 12 reported disordered eating two years later.

The findings suggest that the timing of smartphone ownership may be linked to risk for eating disorders — which experts say have been rising in adolescents since the Covid-19 pandemic partly thanks to social media.

Eating disorders, a group of mental illnesses that involve abnormal and unhealthy eating behaviors, leave people at greater risk of negative health consequences, including an increased risk of premature death.

“A smartphone can put a world of appearance-focused content in a young person’s pocket,” Dr. Jason Nagata, the study’s lead author and an associate professor of pediatrics at the University of California, San Francisco, told CNN.

“It’s important for parents to be aware that getting a smartphone isn’t just about the device. It can change a child’s access to different content and exposures in the digital world,” he said.

A March study in the U.K. found that overusing a smartphone was tied to disordered eating in teens, too — though Nagata and his co-authors said future studies are needed to better understand any association seen in the new study.

The September study also found that 70 percent of 12-year-olds own their own phone, building on February research that showed more than half of 11-12-year-olds had their own phone.

Both studies used data from tweens and teens surveyed as part of the Adolescent Brain Cognitive Development Study: the largest long-term study of brain development and child health in the U.S.

And a separate study published by medical researchers in Philadelphia last December found that giving a kid a smartphone before age 12 could leave them at an increased risk of depression, obesity and insufficient sleep compared to their peers without the devices.

"Our findings suggest that we should view smartphones as a significant factor in teen health, approaching the decision to give a child a phone with care and considering potential impacts on their life and health," Dr. Ran Barzilay, a child psychiatrist at the Children's Hospital of Philadelphia, said in a December statement.

Barzilay told Bloomberg in June that age 13 “seems safer.”

Nagata told CNN that although his study doesn’t provide an answer for what age is okay to give a kid a smartphone, it’s important for parents to stay involved with their children’s digital lives.

For preteens with phones, parents may want to think about establishing rules about phone use and regularly communicating with kids about online content, he said.