Smartphone Use Linked to Being Overweight or Obese

Matías A. Loewy

August 02, 2019

Young people who spend more than 5 hours a day on smartphones are more likely to be overweight and obese. This, experts say, means we need to reconsider strategies and use technology to help promote physical activity in this age group.

The message came from a Colombian study presented at the American College of Cardiology (ACC) Latin American Conference 2019 , which took place between 25th and 27th July in Cartagena, Colombia.

Sedentary Behaviour

"Spending too much time on your smartphone facilitates sedentary behaviour, reduces physical activity, increases the risk of premature death, diabetes, heart disease, different types of cancer, osteoarticular problems, and muscular-skeletal symptoms," the lead author of the study, Mirary Mantilla-Morrón, said in a news release.

She is a physiotherapist specialising in cardiac, pulmonary and vascular rehabilitation at the Centre for Diagnostic Cardiology Research, Caribbean Foundation for Biomedic Research, run by Simón Bólivar University in Barranquilla, Colombia.

"Young people do everything via their mobile, as it has become a minicomputer. But if the person concerned is already obese and does not lead a healthy lifestyle, smartphone use should be minimal, because risk factors already exist," Mantilla told Medscape in Spanish.

Study Details

Together with Dr Miguel Urina-Triana, from the same institution, Mantilla assessed 1060 students (700 women and 360 men) at the Faculty of Health Sciences at the research centre, with an average age of 19 ± 3.6 and 20.3 ± 3.8 years respectively.

The young people answered a questionnaire that included the amount of hours spent on their smartphones and data regarding height and weight, which enabled the researchers to explore the relationship between the level of device usage and body mass index (BMI).

In the first analysis, the researchers found that 274 men and women (25.8%) were overweight (BMI > 25 kg/m2) and 47 (4.4%) were obese (BMI > 30 kg/m2). From this total, 49.8% (160) said they spent more than 5 hours a day on their mobile device.

Only three students who were overweight (1.1%) and none of the obese participants indicated that they used their smartphone between 1-2 hours a day, compared to 19 (2.8%) who were a normal weight.

Mantilla and Dr Urina-Triana confirmed a significant statistical relationship between an increase in BMI and hours spent on a mobile.

A Pearson's chi-squared test enabled them to determine if the two variables of the study are associated or independent from one another.

Association or Cause and Effect?

However, the design of this study did not allow us to establish an unequivocal cause and effect relationship, rather an association, correlation or covariation between the two variables, psychologist Richard Lopez PhD told Medscape in Spanish. He's a researcher at the Department of Psychological Sciences at Rice University, Houston, US, who recently explored the relationship between multitasking in young people and the risk of obesity.

The only way to prove that having too much screen time increases weight "would be to manipulate the participants' exposure and device use and measure the subsequent changes in weight or body mass index," Lopez said.

Mantilla is convinced that intensive smartphone use "does not cause obesity, but it is one of the factors that increases its likelihood".

According to a study of American adolescents published in 2016 and cited by the authors, those that spent more than 5 hours in front of a screen (television, smartphones, video games, computers and tablets) were 43% more likely to become obese, compared to those who spent time doing other activities. This is something that could be attributed, at least in part, to greater consumption of sugary drinks and snacks, and less physical activity.

The study conducted by Lopez also suggests that "overload" by simultaneous use of multiple digital devices increases the likelihood to crave food and reduces self-control, which could cause a weight gain.

Mantilla acknowledges it should also be assessed whether the young people with excess weight were more introvert and spent more time on their phones, instead of being involved in other social activities, "which would further facilitate a sedentary lifestyle," she stated to Medscape in Spanish. "It is a vicious circle."

'Normalised Immobility'

Dr Irene Ventriglia, GP and director of the Healthy Programme for Weight Loss in the Italian Hospital in Buenos Aires, Argentina, is not surprised by the Colombian study. "Nowadays, and more increasingly, a social and cultural aspect is put forward as well as a division between the head and body.

"We spend hours still, seated and lying down in front of a screen which provides us with an image or story. And that disconnection infringes upon those behaviours we have come to call 'healthy'," she told Medscape in Spanish.

Dr Ventriglia added: "A level of immobility and sedentary behaviour has been 'normalised' which comes as no surprise. Literally, people of any age and sex can spend weeks without having walked during the day."

Apps to Encourage Exercise

How do we tackle the problem? For Mantilla, education about healthy living habits from a young age is a key factor. But with smartphones now being omnipresent (the authors state that there are more devices than inhabitants on the planet and that they have become an "inherent part of human life"), the physiotherapist also said it would be interesting to promote downloading applications for mobile devices to encourage physical activity.

"There are countless applications that facilitate movement," she said. "If we say to young people that they cannot use their smartphone, who is going to listen to us? No one. But today the same mobiles warn us if we spend too much time seated or still and encourage us to take an active break or go for a walk."

Mantilla concluded, "We can do countless things on smartphones. But the most important thing is to balance moving around and controlling these secondary risk factors, such as sedentary behaviour and poor diet, which lead to cardiovascular disease."

Mantilla-Morrón M, Urina-Triana M. Obesity associated with the hours of use of the smartphone in university students: The technological slavery of the future. American College of Cardiology (ACC) Latin American Conference 2019. Presentado el 27 de julio de 2019; Cartagena, Colombia.

Lopez RB, Heatherton TF, Wagner DD. Media multitasking is associated with higher risk for obesity and increased responsiveness to rewarding food stimuli. Brain Imaging Behav. 1 Mar 2019. doi: 10.1007/s11682-019-00056-0. PMID: 30820857.

Kenney EL y Gortmaker SL. United States Adolescents' Television, Computer, Videogame, Smartphone, and Tablet Use: Associations with Sugary Drinks, Sleep, Physical Activity, and Obesity. J Pediatr. Mar 2017;182:144-149. doi: 10.1016/j.jpeds.2016.11.015. PMID: 27988020.

Mantilla, Lopez and Dr Ventriglia have declared that they have no relevant conflicts of interest.

Translated and adapted from Medscape Spanish Edition .


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