A new study has found that smartphone ownership at age 12 was associated with a higher risk of several eating-disorder symptoms by age 14, including a more than twofold risk of tying self-worth to weight.
Researchers analysed data from 8,957 US adolescents in the Adolescent Brain Cognitive Development (ABCD) Study to examine whether smartphone ownership at this age was associated with eating-disorder symptoms.
Smartphones at 12 Linked to Eating Symptoms
Of the participants, 6,225 — 69.5 per cent — owned a smartphone at age 12. By age 14, smartphone ownership at 12 was associated with a 49 per cent higher risk of reporting at least one eating-disorder symptom, compared with those who did not own a smartphone at that age.
The findings, published in JAMA Network Open, showed associations rather than proving that smartphones caused eating-disorder symptoms.
'A smartphone can put a world of appearance-focused content in a young person's pocket,' exposing them to pictures and messages that might encourage unhealthy eating habits, lead author Jason Nagata, a youth medicine specialist 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.'
The researchers examined several eating-disorder symptoms separately, including binge eating, inappropriate compensatory behaviours to prevent weight gain, worry about weight gain and tying self-worth to weight.
Binge Eating and Weight Concerns
Among the 6,225 adolescents who owned smartphones at 12, binge-eating symptoms were the most common eating-disorder symptom at that age, reported by 9.2 per cent. By age 14, 24.2 per cent of smartphone owners reported at least one eating-disorder symptom, compared with 15.5 per cent of those who did not own a smartphone at 12.
In the adjusted longitudinal analysis, smartphone ownership at 12 was associated with a 67 per cent higher risk of binge-eating symptoms by age 14. The same group had a 50 per cent higher risk of reporting inappropriate compensatory behaviours to prevent weight gain and a 2.03-fold risk of reporting that their self-worth was tied to their weight.
The researchers also found no significant longitudinal association between smartphone ownership at 12 and worry about weight gain alone.
Social Media and Body Image
The researchers suggest several possible explanations for these associations, including exposure to appearance-focused and comparison-driven content on smartphones and social media.
'When you're comparing yourself to influencers whose images are curated, edited and filtered,' Nagata told CNN, 'that can lead to more body dissatisfaction and poor self-esteem, and then that can be a risk factor for eating disorders.'
The researchers also discuss possible pathways involving exposure to online communities promoting disordered eating, as well as nighttime smartphone use and disrupted sleep. These are proposed mechanisms rather than effects established by the study.
Because the research was observational, it cannot establish that smartphones, social media or appearance-focused content directly caused the eating-disorder symptoms. Other differences between adolescents who owned smartphones and those who did not may also contribute to the observed associations, despite the researchers adjusting for a range of factors.
Why the Age of First Smartphone Matters
Previous research using ABCD Study data has found associations between greater screen time and several eating-disorder symptoms, including binge eating, compensatory behaviours and tying self-worth to weight. What distinguishes the latest study is its focus on smartphone ownership at age 12 and subsequent eating-disorder symptoms at age 14.
The researchers analysed 8,957 adolescents and found that 6,225 — 69.5 per cent — owned a smartphone at age 12. After adjusting for a range of potential confounding factors, smartphone ownership at 12 remained associated with a greater risk of several eating-disorder symptoms at 14.
The study does not establish that delaying smartphone ownership would prevent these problems. Instead, the researchers conclude that the timing of smartphone ownership may be associated with eating-disorder risk and say further research is needed to understand the mechanisms behind the observed associations.
Mitch Prinstein, a psychology and neuroscience professor at the University of North Carolina who was not involved in the study, told CNN that emerging research suggests delaying children's access to smartphones and other devices by six months to a year may benefit their mental health.
However, the researchers behind the JAMA Network Open study did not identify an ideal age for smartphone ownership, and their findings do not show that a specific delay would prevent eating-disorder symptoms.
