Republic and Canton of Geneva
Department of Public Instruction, Culture and Sport
Office for Children and Youth
Child and Youth Health Service
Uses of Digital Technology: Health Risks
July 2017 - Translation by the Editor of "Towards Better Health"
In the course of the last two decades, the use of MITIC (media, images and information and communication technologies) has grown tremendously and children’s access to screens, limited up until now to television, has considerably developed. Today, young children are already exposed to these technological devices. The concerns of the medical and educational world about the possible effects on the health and development of children are the subject of more and more studies and publications.
The use of digital technology for educational purposes and in teaching is gaining momentum. It is important to know the health effects of MITIC and to take into account that the use of these devices for entertainment purposes is also increasing. Most of the problems described below are all the more important as the use of screens comes early and is prolonged. The introduction of digital technology in school is also an opportunity to communicate preventive messages to children and young people for an optimal use of these devices.
This document reviews observed effects, emerging issues, and some precautionary measures to follow (recommendations at the end of the document) and promote proper use of screens and digital technology.
Use by children
Children become familiar very rapidly with these new very attractive devices and develop great ability in manipulating them. More and more, we observe use of mobile devices in very young children, aiming to capture their attention and distract them. From school age, children can regularly be occupied, viewing two screens at once, like television and a laptop.
In Great Britain, a teenager spends on average six hours a day in front of screens. Canadian and American children devote between 7 and a half and 8 hours per day, more than half of their waking hours.
At age 7, a child born today will have already spent one year of his life looking at screens. At age 18, this duration is estimated to be 3 years and at age 80, it is around 18 years of a person’s life spent in front of screens.
Effects on development
Already at the beginning of the 21st century, studies concerning the effect of television on children revealed a relationship between the daily duration of viewing and the risk of developmental and attention deficit disorders with or without hyperactivity (ADHD). For each hour spent by young children aged 1 to 3 in front of the TV, the risk of developing ADHD increased 9%. Similar observations were made in older children and in teenagers and young adults. Curiously, one sometimes observes an “attention paradox” in children who can remain glued for hours to a video game but who, afterwards, are incapable of paying attention to homework, for example, because the attention to external light stimuli (called “bottom-up”) completely exhausts voluntary control of attention (“top-down”) involving motivation, the capacity to tolerate negative emotions and solve a problem.
Games and action films have a negative marked effect on children’s decision-making.
We have observed that dopamine, a neurotransmitter essential to maintaining attention, is secreted in significant fashion in young adults playing online games. Dopamine is also a cerebral component of the system of reward and would thus be implicated in the development and maintenance of an addiction to these games and to viewing screens in general. The problem of addiction affects relatively few young people but can constitute a real health problem, justifying appropriate therapy.
Several studies have clearly shown that children’s use of screens was associated with a delay in speech. Each daily hour of video, so-called adapted and shown to the youngest children, aged 8 months to 16 months, translates into an impoverishment of vocabulary on the order of 10%. Two hours of daily TV for children aged 2 to 4 triples the risk of speech delay. The reason for this is essentially the significant reduction of intra-familial verbal exchanges.
In order to develop, cognitively and emotionally, the child needs interactions with other children and adults. He learns the need to communicate by exploration, touch, and imitation. The viewing of two-dimensional images and interaction with a screen does not favor this learning. Even passive exposure to TV (the child is not watching it but playing in the same room) has a negative effect on the development of the child.
Some studies have also established a significant link between screens (watching TV is the one most studied – since the 1980’s) and academic failure. One study has shown that each hour of daily TV viewing in primary school increased by 43% the risk of a child leaving school without a diploma.
Effects on sleep
Generally speaking, during the course of the last five decades, the daily amount of sleep of the population has decreased on average 90 minutes over 24 hours. If the causes are multifactoral, it has been established that exposure to screens has a profound deleterious effect on sleep. The presence of any screen in the bedroom of a child is inversely correlated with the amount of sleep and probably also its quality. Children’s use of tablets is also associated with a reduction in nighttime sleep, only partially compensated by an increase in daytime sleep of the youngest children.
The probable causes are:
- The delay in going to bed due to looking at screens.
- The psychological and physiological excitation regarding the content of what one is watching, causing a delay in falling asleep.
- The blue light emitted by screens, particularly smartphones, which disturb the physiological circadian rhythm (decreasing the secretion of melatonin).
Effects on physical health
Numerous cohort studies show a significant relationship between exposure time to screens and many diseases that are harmful to health:
-type 2 diabetes
-cardiovascular diseases: hypertension, coronary disease
Sedentariness induced by prolonged exposure to screens certainly plays an important role but does not explain everything. The stress generated by the use of TIC (information and communication technology) over a long period persists even during the night and disturbs the cortisol cycle and the secretion of insulin and raises blood pressure whether the person engages in physical exercise or not.
The attention given to screens also modifies the feeling of satiety and the memory of having eaten, pushing one to eat in erratic fashion which is unhealthy.
Effects on eyesight
The effects of blue light on the eyes have especially been studied along with use of LED lighting. Besides its effect on sleep, blue light can cause retinal lesions.
Limit values exist for exposure which are generally respected but little is still known about long-term effects.
We know that children are more sensitive to blue light and absorb it more easily, which is another reason for limiting their exposure to screens, in particular to smartphones, and to select digital devices with filters.
The prolonged use of screens can also cause dryness and irritation of the eyes and ocular fatigue. It is known that this is also contributing to the epidemic of myopia that we have been seeing for several years, even if other factors also cause this.
Risk of cancer
Electromagnetic fields generated by digital devices are causing concern regarding the potential carcinogenic effects of this radiation. Based on current scientific knowledge, there is no major risk identified, except an eventual small risk of a brain tumor observed in persons significantly using a mobile phone long-term (a device which emits more waves and is used closer to the brain). This has caused the International Agency for Research on Cancer of the World Health Organization to define exposure to these electromagnetic waves as possibly carcinogenic to humans.
The fields generated by wireless installations are below the defined standards and are considered without risk. However, we still know little about the eventual long-term effects. The issue continues to raise concern and controversy and to be the subject of studies. It is important to respect certain rules as a precautionary measure.
Effects on mental and social health
Several studies show negative effects of the use of information and communication technology on mental and social well-being. The interface via a screen is not without consequences on the relational well-being of children and young people.
The American Academy of Pediatrics has published a report on the impact of social networks on children where one section describes « Facebook Depression». Other studies show that children who watch screens too much are more at risk of developing psychological difficulties and have less self-esteem. Several mechanisms raised are:
- less face-to-face contact (co-presence)
- less direct social interaction
- less linguistic competency, and « live » conversations : vocal, body language, non-verbal expression of emotions.
The development of empathy and emotions is mediated by face-to-face contact. The observation and imitation of social behavior is essential to the development of the brain and cannot be made via screens: it is difficult to transpose real life to what one sees on screens. A cerebral MRI study has shown that when one uses the internet, zones of the brain associated with empathy are not stimulated. The more intensive and the earlier the use of media, the less the development of emotional capacity.
Exposure to violent images has three short- and long-term effects :
- it increases the probability of recourse to verbal and physical aggression
- it gets us used to violence and favors the acceptance of violence
- it favors withdrawal and increases our feeling of living in a hostile and malevolent world.
Of course, the general problem of violence in the world largely exceeds the issue of exposure to violent images. That being said, persons unable to develop their psycho-social and linguistic competencies, and their capacity for empathy and emotions (as described above) are also more at risk at using violence to express their frustrations.
The risks linked to use of social networks are significant:
Abuse, cyberbullying, damaging one’s image, threatening one’s identity. These aspects are developed in other documents.
It is also important to warn children and young people about “games” or other programs inciting risky behavior to which they may be confronted. (An example is the Blue Whale which proposes to children a challenge that is at first trivial, then more and more risky that can lead to placing one in significant danger.)
The internet and social networks are also used for propaganda purposes, namely to incite the radicalization of particularly fragile young persons.
Preventive measures and matters for attention
For the well-being and health of children and young people, exposure time to screens must be limited according to age.
At all ages, it is important to promote movement and physical activity and to make children and young people understand the health issues and limit time on “screens” by insisting on the negative effect on sleep and encouraging reading in the evening which has no influence on falling asleep.
The attitude of adults towards MITIC plays an important role. Constant dialogue on use of screens, about everything we are seeing, the promotion of their use for educational purposes and not only for entertainment, the development of a critical look play an essential role for the development of young people and the protection of their health and integrity.
Devices in bedrooms should be limited: no TV, computers, tablets. Cell phones should be banned or switched off depending on the child’s or young person’s ability to take responsibility.
Age and duration of exposure
These are the determining factors favoring optimal use of screens while encouraging the proper development of the child and protection of his health.
The SSEJ proposes the following recommendations1 linked to the age of the child.
The approach is stated positively and not by denouncing problematic practices.
These recommendations take three directions:
a) Learning self-regulation: fixing a schedule for the young child and proposing a contract for an older child.
b) Practicing alternance: varying stimulation and developing activities using the five senses.
c) Support: making the child talk about what he has experienced with screens in order to use his spatial and narrative intelligence.
Before age 3
No TV or DVDs. The child really needs to experience his body in space and in relation to others thanks to psycho-motor and sensorial activities (sight, hearing, touch, smell, movement). He needs to be in relationship with others (language, model, emotions). He is not apt to understand the content of films and DVDs, even educational programs.
From age 2, a tablet can be used 10 minutes per day in the company of an adult who can interact with the child.
Between ages 3 and 6
Television can be allowed with control of the programs. The tablet should also be used in the company of an adult. Limiting the exposure time to screens to one hour a day is desirable.
From age 6
One can introduce video games at this age (avoid violent games). Favor games for several persons allowing interaction between the players (or play as a family). Limit the duration and availability of games. Adults are encouraged to discuss the content with children.
Access to the internet must be limited, controlled, and in the company of an adult.
From this age, the total exposure time to screens should be limited to one hour a day.
From age 9
The child can surf the internet alone provided there is parental control. The child is encouraged to discuss what he sees with adults and talk without delay about what disturbs him.
The exposure time should also be limited to two hours a day for all screens.
Access to social networks must be limited and authorized towards age 12-13. It is important to explain to children the aspects concerning protection of the individual, privacy, the role of images in order to make them conscious of the risks of non-controlled diffusion of what they exchange, of the permanence of what is placed on the internet and favor the development of a critical look at the subject one is reading. www.actioninnocence.org/ http://www.sergetisseron.com/3- 6-9-12/
Following are recommendations of the Federal Office for Public Health aimed at limiting exposure to radiation:
- Only switch your WLAN on when you need it. With laptops, in particular, it is a good idea to switch the WLAN off as otherwise the device will repeatedly try to connect to a network, leading to unnecessary radiation and a shorter battery life.
- Don’t hold your laptop close to your body while it is connected to a WLAN.
- Wherever possible, install the access point one metre away from places where you work, sit or rest for long periods of time.
- Position the access point centrally so that all the devices in the network have good reception.
- Choose the WLAN g standard in preference to the b standard. Exposure to radiation is lower with this standard because it transmits data more efficiently.
- If it is possible to adjust the power of the network, the transmission power should be optimised at the access point for the area that needs to be supplied
- A WLAN transmitter must only be used with an antenna provided for this purpose by the manufacturer. If an unsuitable antenna with an excessive antenna gain is used, the maximum permitted transmission power may be exceeded.
- The measures recommended by the FOPH for reducing radiation exposure when using mobile phones apply to WLAN-enabled mobile phones that are used for Internet telephony
1 Tisseron, S. (2013). 3-6-9-12 Apprivoiser les écrans et grandir. Toulouse : Erès.
Virtually addicted: why general practice must now confront screen dependency. Sigman A. Br J Gen Pract. 2014 Dec;64(629):610-1. doi: 10.3399/bjgp14X682597. No abstract available. PMID: 25452511 Free PMC Article
Time for a view on screen time. Sigman A.
Arch Dis Child. 2012 Nov;97(11):935-42. doi: 10.1136/archdischild-2012-302196. Epub 2012 Oct 8. No abstract available.
Effets de l’exposition chronique aux écrans sur le développement cognitif de l’enfant B. Harlé, M. Desmurget
Arch Pediatr. 2012 Jul;19(7):772-6. doi: 10.1016/j.arcped.2012.04.003. Epub 2012 May 18.
Daily touchscreen use in infants and toddlers is associated with reduced sleep and delayed sleep onset. Cheung CH, Bedford R, Saez De Urabain IR, Karmiloff-Smith A, Smith TJ.
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Les écrans et l’enfant; apprendre à gérer plutôt qu’interdire! Christine Durgnat-Sciboz, Olivier Duperrex, Lausanne Paediatrica Vol. 24 No. 3 2013
Champs électromagnétiques et santé publique : téléphones portables
OMS Aide-mémoire N°193
Original document in French - click on pdf document.
Unofficial translation except for FOPH recommendations.