12-year-olds with smartphones are more likely to develop eating disorders by 14

Kids who have their own smartphones at age 12 are more likely to develop eating disorder symptoms than their peers without the devices, according to a new study.

The research, published Friday in the medical journal JAMA Network Open , comes from a wide-ranging survey of nearly 9,000 adolescents across the United States.

“A smartphone can put a world of appearance-focused content in a young person’s pocket,” exposing them to images and messages that may foster unhealthy eating behaviors, said Dr. Jason Nagata, the study’s lead author. “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.”

It may matter not just whether you get your kid a phone, he said, but when you do it.

Spending time on screens and social media is associated with a range of negative outcomes for kids , including depression, lower feelings of self-worth and experimenting with drugs and alcohol . Past research by Nagata’s lab has found correlations between screen time and binge eating .

Most earlier studies have looked at how much time young people spend on their devices, said Nagata, an associate professor of pediatrics at the University of California, San Francisco. For the new paper, he wanted to focus on the age at which children start using them and how doing so might affect the development of disordered eating down the road.

Around 22% of children and adolescents worldwide show signs of disordered eating , according to research estimates. The distinction between disordered eating and an eating disorder essentially comes down to the level of severity and whether or not a person meets the criteria for a diagnosis. Both may include a fixation on food and weight, distorted feelings about body shape and size, restricted eating, or compensating for calorie intake by throwing up or exercising.

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Using data collected from the Adolescent Brain Cognitive Development Study , a large, long-term study of brain development and health in American children, Nagata and his team found that 70% of 12-year-olds owned their own phone. Of those, 24% reported at least one eating disorder symptom at age 14. By comparison, less than 16% of teens who did not have a smartphone at age 12 reported disordered eating two years later.

The tween years are a crucial time in development, both physically and emotionally. Puberty comes with major changes in body and body image, and it’s natural, Nagata said, for kids to compare themselves with one another.

Before smartphones and social media, those comparisons happened mainly among peers. “But when you’re comparing yourself to influencers whose images are curated, edited and filtered,” he said, “that can lead to more body dissatisfaction and poor self-esteem, and then that can be a risk factor for eating disorders.”

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Kids who had smartphones at 12 were twice as likely to tie their self-worth to their weight and 1 ½ times more likely to have tried controlling their weight by, for instance, eating low-calorie foods or exercising a lot, according to the study.

Holding off on smartphones might spare adolescents from body image issues — at least for a while, said Dr. Mitch Prinstein, the John Van Seters Distinguished Professor of Psychology and Neuroscience at the University of North Carolina at Chapel Hill and codirector of the Winston Center on Technology and Brain Development. Prinstein, who was not involved in the current study, said new research is beginning to find that delaying access to phones and other devices by six months or a year seems to benefit kids’ mental health.

When kids do get their own phones, he recommends parents let them “slowly, gradually get more exposure to social media over time. We don’t want to give them a completely unlocked phone with all the opportunities to visit whatever they want for as long as they want.”

Most major social media platforms set 13 as the minimum age to create an account, Zagata said, yet his past research has found that nearly two-thirds of 11- and 12-year-olds have accounts on platforms such as TikTok and Instagram.

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This latest study doesn’t provide the “magic answer” as to when the ideal time is to get your kids a smartphone, he said. But if parents do entrust preteens with their own phones, they may want to consider “additional guardrails,” such as limiting the apps kids can download and keeping phones out of the bedroom, so it is easier to monitor their activity.

“It’s so important for parents to stay involved with their children’s digital lives,” Zagata said. He recommends establishing ground rules about phone use, having open conversations about what children are seeing online, and paying attention to any changes in how kids eat or how they talk about their bodies.

You might not allow phones at the dinner table, but that could be a good time and place to discuss them.

一项新的研究表明，12岁就拥有智能手机的孩子比没有智能手机的同龄人更容易出现饮食失调症状。

这项研究于周五发表在医学期刊《JAMA Network Open》上，研究对象为美国各地近 9000 名青少年。

“智能手机能让年轻人随时随地接触到大量以外表为中心的资讯，”该研究的主要作者杰森·永田博士说，“这会让他们接触到可能助长不健康饮食习惯的图片和信息。家长们必须意识到，给孩子买智能手机不仅仅是买个设备那么简单。它会改变孩子在数字世界中接触各种内容和信息的方式。”

他说，重要的不仅是你是否要给孩子买手机，还有你何时给孩子买手机。

孩子花太多时间在电子屏幕和社交媒体上，会引发一系列负面影响，包括抑郁、自尊心降低以及尝试毒品和酒精。Nagata实验室之前的研究发现，屏幕时间和暴饮暴食之间存在关联。

加州大学旧金山分校儿科副教授永田表示，以往的研究大多关注青少年使用电子设备的时间长短。而在这篇新论文中，他希望重点关注儿童开始使用电子设备的年龄，以及这种行为可能如何影响他们日后饮食失调的发生发展。

据研究估计，全球约有22%的儿童和青少年表现出饮食失调的迹象。饮食失调和进食障碍之间的区别主要在于严重程度以及患者是否符合诊断标准。两者都可能包括对食物和体重的过度关注、对自身体型和尺寸的扭曲认知、限制饮食，或通过催吐或运动来弥补热量摄入不足。

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青少年几乎所有事情都依赖人工智能。但饮食信息可能存在很大风险。

纳加塔及其团队利用“青少年大脑认知发展研究”（一项针对美国儿童大脑发育和健康的大型长期研究）收集的数据发现，70%的12岁儿童拥有自己的手机。其中，24%的儿童在14岁时报告至少出现过一种饮食失调症状。相比之下，12岁时没有智能手机的青少年中，两年后报告出现饮食失调症状的比例不到16%。

青少年时期是身心发展的关键时期。青春期会带来身体和身体形象的重大变化，孩子们互相比较是很自然的，永田说。

在智能手机和社交媒体出现之前，这种比较主要发生在同龄人之间。“但当你把自己和那些照片经过精心挑选、编辑和滤镜处理的网红比较时，”他说，“这会导致更多的身材不满和自卑，而这可能成为饮食失调的风险因素。”

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研究表明，12 岁时拥有智能手机的孩子，将自我价值与体重联系起来的可能性是其他孩子的两倍，并且尝试通过例如吃低热量食物或大量运动来控制体重的可能性是其他孩子的 1.5 倍。

北卡罗来纳大学教堂山分校心理学和神经科学系约翰·范·塞特斯杰出教授、温斯顿技术与大脑发育中心联合主任米奇·普林斯坦博士表示，推迟青少年使用智能手机或许能让他们暂时摆脱身材焦虑。普林斯坦博士并未参与这项研究，但他指出，新的研究开始发现，推迟六个月或一年使用手机和其他电子设备似乎对儿童的心理健康有益。

他建议，当孩子们拥有了自己的手机后，家长应该让他们“循序渐进地接触社交媒体。我们不想给他们一部完全解锁的手机，让他们可以随心所欲地访问任何内容，想访问多久就访问多久。”

Zagata 表示，大多数主流社交媒体平台将创建账户的最低年龄设定为 13 岁，但他过去的研究发现，近三分之二的 11 岁和 12 岁儿童在 TikTok 和 Instagram 等平台上拥有账户。

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你一直没有制定规则来控制孩子的屏幕时间。现在该如何改变这种情况呢？

他说，这项最新研究并没有提供何时才是给孩子配备智能手机的最佳时机的“万能答案”。但如果家长确实让即将进入青春期的孩子拥有自己的手机，他们或许应该考虑一些“额外的限制措施”，例如限制孩子可以下载的应用程序，以及将手机放在卧室外，以便更容易监控他们的使用情况。

“父母参与孩子的数字生活至关重要，”扎加塔说。他建议父母制定手机使用规则，与孩子坦诚交流他们在网上看到的内容，并留意孩子饮食习惯或谈论自身身体方式的任何变化。

你可能不允许在餐桌上使用手机，但餐桌可能是讨论手机的好时机和好地方。