Time to call time on screen time?

Question 1

What is DST?

Answer 1

Discretionary screen time. Usually related to entertainment purposes

Question 2

What are current rates of screen time?

Answer 2

• in the US 13-18 year olds spend 7.3 hours per day doing DST
• in the UK, by the age of 8 children would have spent a whole year (24 hour days) doing DST
• by 85 spent 20 years on DST

Question 3

DST factors influencing eating and health outcomes

Answer 3

1) amount of screen time
2) location of screen time
3) time on screen time
4) content of screen time

Question 4

COVID impact on DST

Answer 4

DST consumption has increased by 265% in children. Mapping studies have been done where high increases in obesity are expected

Question 5

DST and CVD risk and adults

Answer 5

• independent of PA, time sitting and DST increased all-cause mortality and CVD
• limiting screen time to 2 hours per day may reduce CVD risk by 7.97%

Question 6

Impact of DST on movement

Answer 6

• people almost ‘paralysed’ when watching TV
• in no other sedentary activity were people so still
• over time this would lead to a negative impact on musculature

Question 7

Impact of DST on obesity and BMI

Answer 7

• screen time independent of sedentary behaviour was predictive of higher body fat in children
• in mother and child groups screen time was also associated with higher rates of obesity
• strong associations between DST and insulin resistance and adiposity= increased risk T2DM
• for children, every extra hour of DST per day increased BMI by 0.6 kg/m2

Question 8

How much TIME on DST increases food intake by distraction

Answer 8

• smartphone usage increased kcal intake by 15%
• distraction via DST caused participants to eat 45% more crisps
• will eat more if movie actors are eating

Question 9

How LOCATION of DST influences food intake

Answer 9

• TVs viewing in bedrooms at age 4 predicted higher BMI at age 12 and poorer eating habits at age 13
• TVs in bedrooms increase blue light exposure and lead to poorer quality sleep

Question 10

How the CONTENT of DST influences food intake

Answer 10

• more stressful content increases cortisol, and IL6, CRP which can increase hunger and also have a knock-on effect on atherosclerosis
• violent video games were found to decrease self-control
• screen dependency or ‘gaming disorder’ also causes neurobiological changes with a smaller ventral striatum meaning they have to consume more to feel ‘reward’ (lower levels of dopamine receptors). Which leads to greater rates of obesity/higher BMI

Question 11

How screen time affects sleep and the impact

Answer 11

• blue light (460 nm) causes block in melatonin which leads to poorer quality sleep and can have knock on impact on learning and behaviour
• regularity and length of sleep can predict a child’s BMI
• sleep deprivation also increases ghrelin which increases intake
• activation of the endocanniboid system which increases appetite

Question 12

Recommendations for limiting screen time

Answer 12

• WHO recommends children under 2 have 0 screen time, and those 2-5 only have an hour (max)
• limit non-educational for those older to 1-2 hours per day
• parental monitoring and modelling behaviour can help
• remove TVs from bedrooms
• promote device-free outdoor activities
• exercise outdoors seems to mitigate the negative impact of screen time
• should also include information in maternal packs they leave hospital with
• health professionals should also take a ‘media history’ to check that changes in behaviour are not just due to over-use of screen time