Tag Archives: Millennium Cohort Study

I wanna hold your hand: helping young people prepare for happy healthy relationships

The teenage years are a time for experimenting and for pushing boundaries – particularly when it comes to intimate relationships. Such experimentation is a natural part of growing up. But there are potential risks, too – particularly if these early experiences aren’t positive ones. A new study from Professor Yvonne Kelly from UCL’s Department of Epidemiology and Public  Health  and colleagues, investigates what kinds of intimate behaviour 14 year-olds engage in, and asks how this insight can help to ensure  young people are well prepared for healthy and happy adult relationships.

We know teenagers experiment with intimacy, often moving ‘up’ the scale from hand-holding or kissing to more explicitly sexual activity. But we also know teenage pregnancy numbers have been dropping in recent years. And our new study suggests that fewer young teenagers are actually having sexual intercourse than some might previously have thought. 

We’ve all seen the headlines – studies have shown us (links) that 30 per cent of those born in the 1980s and 1990s had sex before the age of 16, and that among those born in the early 1990s a little under one in five had done so by age 15. But our new evidence, based on 14 year-olds born during or just after the year 2000, paints a rather different picture of this latest generation of teenagers.

Our research used data from the Millennium Cohort Study, the most comprehensive survey of adolescent health and development in the UK. It follows children born between September 2000 and January 2002 and has collected information on them at nine months and subsequently at age  three, five, seven, 11, and  14 years. We used information from the most recently available data, when the study’s participants were 14 years old, and were able to look closely at the lives of 11,000 of them.  

Intimate activities

Participants were asked about a range of ‘light’, ‘moderate’ and ‘heavy’ intimate activities. Handholding, kissing and cuddling were classed as ‘light,’ touching and fondling under clothes as ‘moderate’ and oral sex or sexual intercourse as ‘heavy.’

As might have been expected, more than half – 58 per cent – had engaged in kissing, cuddling or hand-holding, while 7.5 per cent, or one in 13, had experienced touching or fondling. But in contrast to other studies, (though our sample was younger than those mentioned above) we found only a very small proportion – 3.2 per cent or fewer than one in 30 – had been involved in ‘heavy’ activities in the year before they were interviewed for the study.

And most parents can take comfort from the fact that if their children aren’t participating in other risky activities such as drinking or smoking, they probably aren’t having sex either – there was clear evidence of links between heavier sexual activity and these factors.

We also found those who were most likely to confide worries in a friend rather than a parent, those whose parents didn’t always know where they were and those who stayed out late were more likely than others were to be engaged in heavier forms of sexual activity. Other potential links were found to drug-taking and as well as to symptoms of depression.

Our findings suggest young people who push boundaries may push several at once – that those who drink, smoke or stay out late, for instance, are more likely to engage in early sexual activity.

So, initiatives which aim to minimise risk and promote wellbeing are crucial – and they need to look at intimate activities, health behaviours and social relationships in relation to one another. 

A key point is that if young people can learn about intimacy in a positive way at an early stage, then those good experiences can build foundations which will help them throughout their lives.

Most importantly young people need to know how to ensure their intimate experiences are mutually wanted, protected, and pleasurable. The concept of “sexual competence” – used to refer to sexual experiences characterised by autonomy, an equal willingness of partners, being ‘ready’ and (when relevant) protected by contraceptives – is important at all ages, as are close and open relationships with parents.

Better understanding of this interplay between personal relationships and behaviours are key to better support for young people. The right intervention at the right time can ensure a teenager’s intimate life is set on a positive course.

Partnered intimate activities in early adolescence – findings from the UK Millennium Cohort Study, by Yvonne Kelly. Afshin Zilanawala , Clare Tanton, Ruth Lewis and Catherine H Mercer,is published in the Journal of Adolescent Health.

*Afshin Zilanawala is based at the Research Department of Epidemiology and Public Health, University College London, and Oregon State University, United States.

Clare Tanton is based at London School of Hygiene & Tropical Medicine.

Ruth Lewis is based at the University of Glasgow.

Catherine H Merceris based at University College London.

Adolescent mental health and risky behaviour – how have things changed for millennials?


In recent years the incidence of adolescent mental health problems has been rising. But at the same time, risky behaviour such as substance abuse – which has been linked to such problems – has become less common. So what has been going on? Praveetha Patalay from University College London and Suzanne Gage from the University of Liverpool looked at how things have changed over a decade among millennials born in early 1990s and early 2000s.

Headlines about adolescents have been dominated in recent years by concerns about mental health and wellbeing.

We know the prevalence of mental health issues has been rising among this group – and that the phenomenon is not restricted to the UK: international comparisons  have shown the trend is mirrored across the globe.

And there’s a growing recognition that adolescence is a key time in this respect – half of those who suffer later from a mental health disorder experience symptoms by the age of 14.

Changing behaviour

Yet we know from official reports that at the same time, some types of risky behaviour which are linked with poor mental health have become less common among the young. Adolescents in the UK are less likely to be under-age substance abusers, and the proportion of 14 year-olds who smoke regularly has dropped to just a quarter of what it was in 1982.

A new piece of research looks at how rates of different mental health and health related behaviours such as substance use but also sleep, weight perception and underage sex are changing.  

The paper looks at data for two cohorts of UK adolescents – those who were 14 in 2005 and those who were the same age in 2015. It uses data from two UK birth cohort studies – 5,627 young people born in 1991-2 who were part of the Avon Longitudinal Study of Parents and Children, and  11,318 born 2000–02 who were part of the Millennium Cohort Study.

The researchers looked at trends in mental health problems such as depression and self-harm, and found a picture broadly similar to previous studies. These phenomena had become more prevalent over time, with the incidence of high levels of depressive symptoms rising from six per cent in 2005 to 15 per cent in 2015. In contrast with some other studies they found boys had suffered an increase just as great as girls.

Poor mental health in our teenage years can predict a whole range of negative outcomes later on – poor physical health, worse job prospects and poor personal relationships, for instance.

Behaviour and health

And yet these results showed significant drops in various types of behaviour which are linked with poor mental health. For instance, the proportion who had assaulted someone at age 14 dropped from 40 per cent in 2005 to 28 per cent in 2015. Fewer young people had tried alcohol, binge drinking, smoking or having sex by the age of 14. 

In this sample, young people in 2015 were more likely to have later bedtimes, to wake up earlier and to sleep less than the recommended eight hours. They were more likely to see themselves as overweight and to have higher Body Mass Index, or BMI. 

These relationships aren’t simple. Other factors have changed over time, too. For instance the proportion of young people from ethnic minority backgrounds has risen, though that was taken into account. 

The researchers suggest that increasing trends in risky behaviours such as decreasing sleep times, increasing weight and poor body image need to be investigated as potential explanatory factors for increasing mental health difficulties experienced by adolescents.

But there are some clear findings from this study. The rapid increase in depressive symptoms, self-harm, obesity and loss of sleep in adolescents over the past decade is an important finding in itself, and understanding the reasons for this could be a priority for both practitioners and policy-makers.

Changes in millennial adolescent mental health and health-related behaviours over 10 years: a population cohort comparison study is research by Praveetha Patalay and Suzanne H Gage and is published in the International Journal of Epidemiology.

Teenage depression: The potential pitfalls of too much social media use

A new mobile phone will be in the pockets of many teenagers as they head back to school in the coming days. The period between Xmas and New Year will have been spent signing up for social media apps where they can chat, share photos and videos with friends, all part of the excitement of owning a new device. But how many of these young people and their parents are aware of the potential pitfalls of spending too much time on social media sites?  And what can parents, teachers and young people themselves do to maximize the benefits of life online whilst minimising those pitfalls? It’s a question that Yvonne Kelly, Director of the ESRC International Centre for Life course Studies at UCL and colleagues have been asking as part of a major programme of research on social media use and young people’s wellbeing. Today they publish key new research, which provides much-needed new evidence on the links between heavy social media use and depression in teenagers. The research shines light on the underlying processes that could be at work and that might explain the link between the two. Here, Yvonne explains how their research might help policymakers, educators, parents and young people themselves better understand and prevent the potential pitfalls of living too much of their life on social media platforms.

2018 has seen a growing chorus of voices including those of the former and current Health Secretaries, Jeremy Hunt and Matt Hancock calling for a thorough investigation of the links between social media use and the growing numbers of young people struggling with mental health issues. Indeed Matt Hancock issued “an urgent warning” on the potential dangers of social media on children’s mental health, stating that the threat of social media on mental health is similar to that of sugar on physical health.

The Chief Medical Officer, Dame Sally Davies has been tasked by the Government with leading that investigation and with coming up with evidence based recommendations around what constitutes safe social media use and what changes need to be made and by whom to make that a reality. The Royal College of Paediatrics and Child Health (RCPCH) recently issued the first ever guidance on managing children’s screen time, calling for further research particularly into social media.

In recent months, we and others have submitted written and oral evidence to two Parliamentary inquiries in this area and had discussions with the Royal Society for Public Health which is campaigning actively  to get us all thinking harder about our social media use.

We’ve talked about our early research  showing that 10 year-old girls who used social media sites for chatting had more social and emotional problems at age 15 than their peers who used them less or not at all. Those problems continued to get worse as they got older.

Our new research published in The Lancet’s EClinical Medicine draws stronger links between heavy social media use and depressive symptoms in girls and boys at the age of 14.  We look at the possible ways in which social media use might linked to depressive symptoms. We consider 4 potential pathways – through young people’s sleep patterns, their experiences of online harassment, body image and self-esteem. It is the first research to look at all of these potential pathways at the same time.

Our data for this research came from the Millennium Cohort Study, which has followed the lives of some 19,000 children born at the turn of the century. This piece of research, looked at the social media use and mental health of nearly 11,000 of the study’s participants.

Social media use

In line with our earlier research, we saw that girls were heavier users of social media than boys with two fifthsof them using it for more than 3 hours per day (compared with one fifthof boys). Girls were a lot less likely NOT to use social media at all (4 per cent girls and 10 per cent boys).

Examining the underlying processes that might be linked with social media use and depression, we saw a number of really striking findings including:

  • 40 per cent of girls and 25 per cent of boys had experience of online harassment or cyberbullying
  • 78 per cent of girls and 68 per cent of boys were unhappy with their body/weight and 15 percent girls and 12 per cent of boys were unhappy with their appearance
  • 13 per cent of girls and 9 per cent of boys had low self-esteem
  • 13 per cent of girls and 11 per cent of boys reported getting fewer than 7 hours sleep per night and 40 per cent of girls and 28 per cent of boys said their sleep was often disrupted

Girls, it seems from these findings, are struggling more with these aspects of their lives than boys – in some cases considerably more. When we turned our attention to the signs of depression exhibited by our participants, we could see that here too girls fared worse with scores on average twice as high as those of boys.

The link between social media use and depressive symptoms was stronger for girls compared with boys. For girls, greater daily hours of social media use corresponded to a stepwise increase in depressive symptoms and the percent with clinically relevant symptoms. For boys, higher depressive symptom scores were seen among those reporting 3 or more hours of daily social media use.

There was a clear link between social media use and all the pathways we investigated – more time spent on social media related to having poorer sleep, more experiences of on-line harassment, unhappiness with the way they look and low self esteem. In turn, these things were directly related to having depressive symptoms.

A closer look at the pathways was also revealing. The most important routes from social media use to depressive symptoms were shown to be via poor sleep and online harassment.

Social media use linked directly to having poor sleep which in turn was related directly to having more depressive symptoms. The role of online harassment was more complex, with multiple pathways through poor sleep, self-esteem and body image, all of which linked directly to depressive symptoms.

Potential pitfalls and key routes

Our findings add weight to the growing evidence base on the potential pitfalls associated with lengthy time spent engaging on social media. In particular they point to poor sleep and online harrassment as being key routes between social media use and depression.

These findings are highly relevant to current policy development on guidelines for the safe use of social media and calls on industry to more tightly regulate hours of social media use for young people. They add weight to the Screen Time Guidance issued by the RCPCH today, particularly the suggestion to set and agree child appropriate time limits on screen use.

When it comes to social media use specifically, our research indicates that the a similar approach could be useful. Clinical, educational and family settings are all potential points of contact where young people could be encouraged and supported to reflect not only on their social media use, but also other aspects of their lives including on-line experiences and their sleep patterns.

At home, families may want to reflect on when and where it’s ok to be on social media and agree limits for time spent online. Curfews for use and the overnight removal of mobile devices from bedrooms might also be something to consider. School seems an obvious setting for children and young people to learn how to navigate online life appropriately and safely and for interventions aimed at promoting self-esteem. Clearly a large proportion of young people experience dissatisfaction with the way they look and how they feel about their bodies and perhaps a broader societal shift away from the perpetuation of what are often highly distorted images of idealised beauty could help shift these types of negative perceptions.

As we head into 2019, millions of young people will be getting their first experiences of life online using the devices they got for Xmas. They will rapidly become expert at downloading apps, posting photos and interacting with their peers. With the gift there was no instruction manual to help them understand and navigate some of the pitfalls our research outlines. We hope our work brings, at least, some guidance for all those keen to ensure these children continue to thrive and do well, so that they enjoy the benefits that new digital technology brings whilst staying safe and happy.

Social media use and adolescent mental health: Findings from the Millennium Cohort Study is research by Yvonne Kelly, Afshin Zilanawala, Cara Booker and Amanda Sacker and is published in The Lancet’s EClinicalMedicine journal.

Taking time out to scroll free

As the Royal Society for Public Health launches its #ScrollFreeSeptember campaign, encouraging people to take a break from social media, Professor Yvonne Kelly from the ESRC International Centre for Lifecourse Studies at UCL, discusses new research on the negative impacts of social media use on young people’s health. She explains how the findings point to the need to limit the time that young people, especially girls, spend on social media.

The ScrollFreeSeptember campaign accompanies the launch of a second parliamentary inquiry in less than 12 months into the impact of social media use on young people’s mental health and well-being. Our Centre will be submitting a range of important new findings to that inquiry which seeks to grow the evidence base in an area where there is a great deal of hot debate, but where little is really known and understood.

For our team of researchers, the first indication that all was not well in the world of social media and young people’s mental health came in 2015 when we found that children who were heavy users of screen-based media were less happy and had more social and emotional problems than their peers who used it moderately. Children who used social media sites for chatting were also less likely to be happy and more likely to have problems than their peers who did not.

In March this year, our widely covered work on the trends for boys’ and girls’ social media use added weight to recent calls from the Children’s Commissioner for England to, as she put it, call time on a “life of likes”. In her report, Anne Longfield argued that there was clear evidence of children finding it hard to manage the impact of online life. She said children as young as eight were becoming anxious about their identity as they craved social media likes and comments for validation.

Social media and girls

Our research, based on the experiences of 10,000 children aged 10-15 who took part in the Understanding Society study, showed that this seemed to be the case particularly for girls who used social media for more than an hour a day. 10 year-old girls in the study who spent an hour or more on a school day chatting online had considerably more social and emotional problems later on – by age 15 – than girls of the same age who spent less or no time on social media. The number of problems they faced also increased as they got older, which was not the case for boys.

It was interesting to note that more girls than boys were using social media and for greater periods of time. At age 15, 43 percent of girls and 31 per cent of boys were using it for between one and three hours per day, with 16 and 10 per cent using it for more than four hours.

We think this tells us something important about the different ways that girls and boys interact with social media. For example, girls may be more likely than boys to compare their lives with those of friends and peers – whether those are ‘filtered’ selfies or positive posts about friendships, relationships or material possessions – these could lead to feelings of inadequacy, lower levels of satisfaction and poorer wellbeing.

The pressures associated with having peers like or ‘approve’ status updates and a perceived fall in or lack of popularity could add further pressure at, what for many teenagers is a tricky time in their lives.

Boys are more likely to be gaming than interacting online in the way just described and that wasn’t covered in this research, so it’s possible that for boys, changes in well-being may be more related to gaming success or skill.

But one of the key takeaways of this research is how social media use as a very young person is linked to lower levels of happiness later on – the effects are not short term – they have longer term consequences and

Social media and depression

More recently, we have turned our attention to the social media experiences of the children in the Millennium Cohort Study (MCS), using information on 11,000 14 year-olds to look at how social media use is linked with depression. We’ve also been asking ourselves what the pathways between these two things might look like, something that’s not really been done before. So, for example, are heavier users of social media getting too little sleep or having trouble getting to sleep because they are checking accounts at bedtime; are they experiencing cyberbullying either as victims or perpetrators; do they appear to have low self-esteem or a negative view of how they look? All these questions can help us better understand what’s at play and come up with better approaches to tackling these problems.

Preliminary findings reinforce the message that girls are particularly vulnerable to the negative effects of social media. Once again we see more girls than boys in this study using social media and for longer periods of time.

Does using social media affect literacy?

A follow up piece of research looks at whether there are links between the amount of time young people spend on social media and their levels of literacy. Findings suggest a link and that this is the same for boys and girls.

In this research we look at whether the more time young people spend on social media, the less time they have for the things that might improve their literacy such as reading for enjoyment and doing homework.

There are some clear messages from our research so far:

  1. Heavy users of social media are less happy and have more problems at school and at home – interventions to help them limit and manage their social media use better are likely to be important
  2. Girls are particularly vulnerable to the negative effects of social media and may be an important group to focus on among those looking to mitigate thse effects
  3. More hours spent on social media appear to impact negatively on young people’s wellbeing and could have knock on effects for their longer term prospects at school and work

Social media companies have been accused by the former Health Secretary Jeremy Hunt among others of turning a blind eye to the problem and the chief medical officer Dame Sally Davies has been asked to recommend healthy limits for screen time.

Our research indicates that it may indeed be time for recommended healthy and safe limits of social media use, that a focus on girls, especially initiatives to boost their mental health could help mitigate some of the negative effects.

The RSPH is hoping that going scroll free this September might give us all a chance to get our social media use a little more balanced, to think about the benefits to be enjoyed and the negatives to be avoided.

As well as pausing to think about our social media use and how it affects us, it will be an opportunity to examine the facts of the matter, a time to digest new, solid evidence that these large scale studies can help us with and consider the potential longer term costs and consequences of doing nothing.

The forthcoming inquiry hopes to inform “progressive and practical solutions”, including a proposed industry Code of Practice and tools for educators, parents and young people themselves to help them enjoy the benefits and eliminate the negative effects of their social media. We wholly support those efforts and hope they result in positive changes that will make campaigns like ScrollFreeSeptember unnecessary in the future.

Wheezing: Can breastfeeding for longer make a difference?

Public health bodies put a lot of effort into encouraging mothers to breastfeed, and for good reasons. Successive studies have shown breastfeeding has a range of health benefits, including a lower risk of wheezing illnesses, which can be linked to asthma. But which of these illnesses are most likely to respond? Is a breastfed child less likely to develop wheezing after age five, or age seven, for instance? Or is the protective effect mainly measurable only in younger children? Professor Maria Quigley from the National Perinatal Epidemiology Unit at the University of Oxford, along with colleagues at Oxford and UCL, has been looking at how and when breastfeeding is associated with wheezing.

Asthma is the most common chronic condition affecting children and young people in the UK. It’s the most common reason why children are admitted to hospital, and sadly each year a few still die from the condition. According to the British Lung Foundation three children in every hundred under the age of five have been diagnosed with asthma at some point; and by age 10 that figure rises to one in 10.

There’s no cure, and so the priority for public health bodies has been to understand the disease better, to manage it better and to learn more about the factors that can protect us from it. One such protective factor is breastfeeding: two recent pieces of research have shown there is a lower risk among breastfed children, but that the effect is stronger among the very young – both for asthma and for wheezing, which has many causes and which does not necessarily develop into asthma.

Childhood wheezing can follow a variety of patterns – it can set in early but clear up before adulthood, for instance, or it can start later but continue into later life. Some wheezing will start in childhood and will continue.

Millennium Cohort Study

We wanted to look at how breastfeeding might affect these different types, so we used data from the Millennium Cohort Study, which has followed the lives of almost 19,000 children born in the UK between September 2000 and January 2002. Their parents were interviewed when they were 9 months old, and again when they were 3, 5, 7 and 11 years.

Our study focused on just over 10,000 children who were seen at all of those points and who were the product of single as opposed to multiple birth. Mothers were asked whether they had tried to breastfeed, and for how long their children had been breastfed.

Among our sample, seven out of 10 children had been breastfed: a little more than one in ten of the study sample for less than a week; a fifth for between one and three weeks, just over one in six for three to six months and around a quarter for six to nine months.

We found that at age 9 months, 6.5 per cent of children had a history of wheezing. At age 3 years, 19.5 per cent had such a history in the past year. As the children got older, though, this proportion decreased – 16 per cent at age five, 11.8 per cent at age seven and 11.4 per cent at age 11.

Overall, 37 per cent of children had suffered from wheezing at least once between 9 months and 11 years. A little under a fifth (18.8 per cent) had wheezing at younger age which cleared up when they got older, while 6.2 per cent had wheezing which started later and 11.8 per cent had persistent wheezing.

Feeding and wheezing

When we looked at the association between breastfeeding and wheezing, we found the children who had been breastfed for longest were less likely to suffer from wheezing.

But this effect lessened with time. For example, those breastfed for six to nine months were less likely to wheeze between the ages of nine months and five years, but by the age of 11 this group had no significant advantage over those who were breastfed for less time.

What does our study tell us about the relationship between breastfeeding and wheezing? The picture is a complex one. There are many causes of wheezing and of asthma, and those causes change over time. So in order to draw firm conclusions about cause and effect, we would need a much more complex dataset. It would be interesting, for instance, to look at clinical information on children’s allergies or their lung function.

But what we can say is that age matters – in order to understand how breastfeeding affects the development of wheezing during childhood, we must take a longer and more nuanced view.

Breastfeeding And Childhood Wheeze: Age-Specific Analyses and Longitudinal Wheezing Phenotypes as Complementary Approaches To The Analysis Of Cohort Data is research by Maria Quigley (University of Oxford), Claire Carson (University of Oxford) and Yvonne Kelly (UCL). It is published in the American Journal of Epidemiology.

Calling time on a life of likes could be key to girls’ happiness

There have been increasing calls in recent months for more to be done to prepare children for the emotional demands of social media. Just a few weeks ago, the Government’s Science and Technology Committee announced an inquiry into the impact of social media on the health of young people. But do girls and boys use social media as much as each other and is all this time spent Facebooking, Whatsapping and Snapchatting having a detrimental effect on their happiness and well-being? Cara Booker from the University of Essex, in collaboration with collleagues from UCL, has been looking at trends in social media interaction and well-being in nearly 10,000 10-15 year-olds in the UK over a 5 year period. Their findings indicate that girls may be at greater risk and therefore a focus for those looking to intervene to protect and promote children’s happiness.

The Government’s inquiry into the impact of social media on the health of young people comes hard on the heels of a report from the Children’s Commissioner for England, which says that children between the ages of 8 and 12 find it hard to manage the impact of online life and become anxious about their identity as they crave ‘likes’ and comments for validation. 

An explosion in digital and social media platforms has revolutionised the way we all consume media with a recent report showing that young people aged 12-15 spending more time online than they do watching TV. Indeed, it seems a long time ago that parents’ prime concern around media was how much or what kind of TV their child was watching.

All these major developments have taken place at a time when we also know that young people are becoming less and less happy. In the most recent United Nations Children’s Fund report, UK adolescents are ranked in the bottom third on overall well-being, below Slovenia, the Czech Republic and Portugal.

Of course, it’s important to remember that the internet has done a great deal of good for children: connecting them with friends and family who may be far away, providing great opportunities to widen horizons and learn new things. These things have been shown in other studies to be linked with increased levels of happiness and well-being in children

On the negative side, social media use has been linked with obesity, cyberbullying, low self-esteem and lack of physical activity, all things that can affect the lives of children as they move through school and into adulthood and work.

Social media experiences

Young people who took part in the Understanding Society survey, were asked if they belonged to a social web-site and then how many hours they spent ‘chatting’ or ‘interacting with friends’ on a normal school day. They could select a range of responses from none to more than 7 hours.

At age 10, 50 per cent of girls and 55 per cent of boys said they had no internet access or spent no time on social media. At 15 years, this dropped to 8 and 10 per cent respectively.

Ten per cent of ten year old girls reported spending one to three hours a day (compared with 7 per cent of boys) and this increased to 43 per cent of girls at age 15 (and 31 per cent of boys).

At age 10 only a very small percent of girls/boys were spending 4 hours plus a day on social media. But by the age of 15, that rose to 16 per cent of girls and 10 percent of boys.

Levels of happiness 🙂 🙁

Young people who took part in the survey were asked about satisfaction with schoolwork, friends, family, appearance, school and life as a whole and this was used to create an overall happiness score for them.

They were also asked about any social and emotional difficulties they might be facing using the well-established Strengths and Difficulties Questionnaire (SDQ) with a higher score indicating more problems.

For both boys and girls, levels of happiness decreased between the ages of 10 and 15, however the decrease was greater for girls than for boys. Additionally, whilst SDQ scores increased for girls between the ages of 10 and 15, they decreased for boys.

10 year-old girls who spent an hour or more on a school day chatting online had higher SDQ scores (more social and emotional problems) than girls of the same age who spent less or no time on social media. In addition, the score (number of problems) increased as they got older.

Why the gender difference?

So why the gender difference? This is hard to unpick and not something we were able to look at specifically in our research. It may say something about the different ways that girls and boys interact with social media. For example, girls may be more likely than boys to compare their lives with those of friends and peers – whether those are ‘filtered’ selfies or positive posts about friendships, relationships or material possessions – these could lead to feelings of inadequacy, lower levels of satisfaction and poorer wellbeing.

The pressures associated with having peers like or ‘approve’ status updates and a perceived fall in or lack of popularity could add further pressure at, what for many teenagers is a tricky time in their lives.

Boys are more likely to be gaming than interacting online in the way just described and that wasn’t covered in this research, so it’s possible that changes in well-being may be more related to gaming success or skill.

What needs to change?

It’s clear that social media is no short-lived phenomenon and our research indicates that girls, possibly because of the way in which they interact online and the amount of time they spend doing so could be at greater risk.

In her report, A Life of Likes, the Children’s Commissioner Anne Longfield has called for more to be done to check and stop underage use and to prevent children becoming over dependent on likes and comments and “adapting their offline lives to fit an online image”, something she believes can lead to an anxiety about ‘keeping up appearances ‘ as they get older.

Our research really adds weight to recent calls for the technology industry to look at in-built time limits. Young people need access to the internet for homework, for watching TV and to keep in touch with their friends of course, but a body of evidence is emerging to show that substantial amounts of time spent chatting, sharing, liking and comparing on social media on school days is far from beneficial especially for girls.

Gender differences in the association between age trends of social media interaction and wellbeing among 10-15 year olds in the UK, is research by Cara Booker (University of Essex), Yvonne Kelly (University College London) and Amanda Sacker (University College London) and is published in BMC Public Health.

Off the scales: time to act on childhood obesity

By 2050, it is said that obesity could cost the NHS almost £10 billion a year, with the full economic cost rising from around £27 billion today to £50 billion by then. Today, the Centre for Social Justice (CSJ) publishes its report, Off the scales: time to act on childhood obesity. It calls on the Government to put prevention, health, inequality and cross-departmental collaboration at the heart of its efforts to tackle childhood obesity, drawing particular attention to the need to address the question of why poorer children are at ever greater risk of being obese. It’s a question researchers at the ESRC International Centre for Lifecourse Studies at UCL, including our editor Yvonne Kelly, have been among the first to address.

There have been numerous major studies on childhood obesity over the past 10 years, many of which have shown the links with poverty. But our research looks specifically at why children from disadvantaged families are significantly more likely to be obese than their better off peers.

To examine this as robustly and rigorously as we could, we used data from the Millennium Cohort Study (MCS) which has tracked the lives of nearly 20,000 children from across the UK since the turn of the century. Using a range of measurements taken when the children were aged 5 and 11 together with detailed information about their backgrounds and family circumstances, we were able to demonstrate just how key poverty was in respect of their obesity.

At age 5, poor children were almost twice as likely to be obese compared with their better off peers. By the age of 11, the gap had nearly tripled.

Knowing as we do that obese children are less likely than their peers to grow into economically successful adults and that obesity is clearly linked with a range of chronic diseases, it’s reasonable to say that for these children, the future is far from bright. From a policy perspective it is also clear that unless the gap between rich and poor children can be closed the chances of reducing the overall obesity trend, as the Government states it is committed to doing, are pretty slim.

How is poverty linked to obesity?

The MCS collects a broad range of data, allowing us to dig beneath these headline numbers to tease out some of the specific ways in which relative poverty in childhood leads to an increased risk of obesity.

To examine this question of whether a parent’s own lifestyle might have a role, we looked at factors previously shown to be linked to the increased risk of obesity, such as whether the mother smoked during pregnancy, how long she breastfed for and whether the child was introduced to solid food before the age of four months.

We could also factor in the degree to which a mother was herself overweight or obese and assess children’s physical behaviour, such as how often they exercised, played and how many hours they spent watching TV or playing on a computer, and the time that they went to bed. We looked at whether the child skipped breakfast, how much fruit they ate and how often they had sweet drinks.

A lot of these factors were relevant. A mother’s behaviour when her child was very young was certainly important. Markers of an ‘unhealthy’ lifestyle here could mean as much as a 20 per cent additional risk of obesity for a child.

Obese and overweight children living in poor families were more likely to have mothers who did not breastfeed or breastfed for a shorter duration, who introduced solid foods early in infancy, who smoked during pregnancy, and who were overweight or obese. The poorest children were also more likely to spend more time watching TV and using a PC (and so have greater exposure to food and drink advertising), experience later and more irregular bedtimes, do less sports and be more physically inactive, engage less in active play with their parent, live in an area without a playground, and not have breakfast every day.

5-year-olds from poorer families were also much more likely to gain excess weight up to age 11 than richer children, leading us to conclude that the earlier certain risk factors can be challenged and the appropriate support provided for the least well off families, the greater the chance of positive impact on the risk of obesity and in a reduction in inequality.

Pathways to obesity

More recently we have identified four BMI trajectories for children. The good news is that 80 per cent of them are on a stable path where, on average, from when they’re born through to age 11, they are not overweight.

There is a small group of children who are obese at age 3 but then join the stable group by age 7. We call them the ‘decreasing’ group. There is a ‘moderate increasing group’ (13.1 per cent) where children are not overweight at age 3 but whose BMIs increase throughout childhood into the overweight (but not obese) range. Finally we have a ‘high increasing’ group of children (2.5 per cent) who are obese at age 3 and whose BMI continues to increase.

From an inequality perspective, what’s most striking here is that the wealthiest children are least likely to be in the ‘moderate increasing’ BMI group whilst the poorest children are more than twice as likely to be on the high increasing path.

Today’s CSJ report agrees with our analysis that early intervention is key and, in line with it, proposes three key early years intervention opportunities to ensure children get the healthiest start possible before they reach primary school age.

The report acknowledges that the Government is already trying to persuade families to eat more healthily and take more exercise. But it has joined a body of voices critical of the Childhood Obesity Plan, which, it believes, “fails to put reducing inequality as a goal … despite acknowledging that the childhood obesity burden falls hardest on the poorest children.”

Certainly our body of evidence indicates that policy makers need to acknowledge and address inequality as a root cause of obesity. Doing something about the structural factors in people’s lives is what is needed rather than ‘tinkering around the edges’ of the problem.

Today the CSJ asks why there are disproportionately high levels of obesity, particularly childhood obesity, in our most deprived communities. Our research has gone some way to answering that question, and makes it clear that there is no simple one-stop shop solution.

Obesity is caused by a combination of environmental, biological, cultural and psychological factors, where one factor does not dominate and yet our obsessional search for the ‘one thing’ that can tackle obesity continues. If the Government is going to reduce obesity rates, it will indeed, need to introduce multiple bold measures in tandem across the entire ecosystem and recognise that success may only be measurable after a few years.

Why are poorer children at higher risk of obesity and overweight? A UK cohort study is research by Alice Goisis, Amanda Sacker and Yvonne Kelly and is published in the European Journal of Public Health

BMI Development and Early Adolescent Psychosocial Well-Being: UK Millennium Cohort Study is research by Yvonne Kelly, Praveetha Patalay, Scott Montgomery and Amanda Sacker and is published in Pediatrics

An equal start: longitudinal evidence to support children’s healthy development

Using longitudinal evidence to support children’s healthy development and give them an equal start in life is the subject of our editor Yvonne Kelly’s keynote address at the Growing up in Ireland Annual Conference in Dublin today.

Her talk discusses findings from the most recent of the British ‘birth ‘ cohort studies – the Millennium Cohort Study that have so far informed policy development. They include work by researchers at the ESRC Centre for Lifecourse Studies where Yvonne is based on alcohol consumption during pregnancy, breastfeeding and the introduction of solid foods, the physical punishment of children , childhood obesity, reading to children in the early years, and sleep patterns throughout childhood.

She will also share work with the potential to inform future policy challenges such as young people’s drinking, social media use and mental health.

Ahead of her talk, she said:

“It is well established that what happens in the early years of life has long-lasting consequences for health and social success across the lifespan. Stark social inequalities in children’s health and development exist and emerge early in life. It is therefore crucial to identify potential tipping points and opportunities for intervention   during childhood with the potential to affect change and improve life chances.”

 

 

Don’t let the kids get jet-lag: why regular bedtimes are key to a happy healthy childhood

The very best of sleep medicine and research is being presented at the World Sleep Congress in Prague this week. Among that research are findings from work by Child of our Time Editor, Professor Yvonne Kelly and colleagues at the ESRC International Centre for Lifecourse Studies. They have been trying to find out what it is about sleep that matters most when it comes to giving children the best possible start in life. Here Yvonne explains what they have found to date and why regular bedtimes are key to a healthy happy childhood.

What happens in the early years has profound implications for what happens later on in life. Thousands of research papers, many of them using the wonderful rich data in the British Birth Cohort studies, have documented the enduring impacts of the way we live our lives as children on how we fare later on. Children who get a poor start in life are much more likely to experience poor outcomes as adults, whether that’s to do with poor health or their ability to enjoy work and family life later on.

So what has all that got to do with getting enough sleep as a toddler you might ask? Well our research shows it is one of a number of important factors related to getting children off to the best possible start in life and here’s why.

Recommended sleep

The National Sleep Foundation recommends that toddlers should get around 11 to 14 hours sleep every day. For 3-5 year-olds, the recommendation is 10-13 hours and it suggests 9-11 hours for children once they’re at primary school. But is it all about the number of hours sleep children get, or is there more to it than that? Those are the questions we have been addressing in our research into children’s sleep and how it ties in with how they get on at home and at school across the first decade of their life.

Digging into one of those studies mentioned earlier, the Millennium Cohort Study, which has followed the lives of some 20,000 children since the turn of the century, we found that it’s not just the number of hours a child sleeps that matters, but also having consistent or regular bedtimes.

First we looked at the relationship between regular and irregular bedtimes and how the children got on in a range of cognitive tests. The results were striking. Children with irregular bedtimes had lower scores on maths, reading and spatial awareness tests.

Parents who took part in the MCS were asked whether their children went to bed at a regular time on weekdays. Those who answered “always” or “usually” were put in the regular bedtime group, while those who answered “sometimes” or “never” were put in the irregular bedtime group.

Interestingly, the time that children went to bed had little or no effect on their basic number skills, and ability to work with shapes. But having no set bedtime often led to lower scores, with effects particularly pronounced at age three and the greatest dip in test results seen in girls who had no set bedtime throughout their early life.

The key to understanding all this is circadian rhythms. If I travel from London to New York, when I get to there I’m likely to be slightly ragged because jet lag is not only going to harm my cognitive abilities, but also my appetite and emotions. That’s for me, an adult. If I bring one of my children with me and I want them to do well at a maths test having just jumped across time zones, they will struggle even more than I will. The body is an instrument, and a child’s is especially prone to getting out of tune.

The same thing happens when children go to bed at 8 p.m. one night, 10 p.m. the next and 7 p.m. another — we sometimes call this a “social jet lag effect.” Without ever getting on a plane, a child’s bodily systems get shuffled through time zones and their circadian rhythms and hormonal systems take a hit as a result.

Bedtimes and behaviour

Having established the importance of sleep to a child’s intellectual development, we turned our attention to the relationship between regular bedtimes and their behaviour.

At age 7, according to parents and teachers, children in the MCS who had irregular bedtimes were considerably more likely to have behaviour problems than their peers who had a regular bedtime. In addition, the longer a child had been able to go to bed at different times each night, the worse his or her behaviour problems were. In other words the problems accumulated through childhood.

One really important piece of good news was that we found that those negative effects appeared to be reversible, so children who changed from not having to having regular bedtimes showed improvements in their behaviour. There seems to be a clear message here that it’s never too late to help children back onto a positive path and a small change could make a big difference to how well they get on. Of course, the reverse was also true so the behaviour of children with a regular bedtime who switched to an irregular one, worsened.

Bedtimes and obesity

In a follow up study, which looked at the impact of routines including bedtimes on obesity, we reported that children with irregular bedtimes were more likely to be overweight and have lower self-esteem and satisfaction with their bodies.

In fact, of all the routines we studied, an inconsistent bedtime was most strongly associated with the risk of obesity, supporting other recent findings which showed that young children who skipped breakfast and went to bed at irregular times were more likely to be obese at age 11.

Even children who ‘usually’ had a regular bedtime were 20 per cent more likely to be obese than those who ‘always’ went to bed at around the same time.

So we have a body of robust evidence now that shows very clearly that regular bedtimes really matter when it comes to a child’s health and development over that important first decade of their life.

Providing that evidence in the form of advice to parents and all those caring for young children alongside recommended hours of sleep could make a real difference, helping protect our children from ‘social jet-lag’ and getting them off to a flying start instead.

Why reading is key to giving our kids a great start in life

A growing body of research is pointing to how important and valuable reading is in giving children the best possible start in life, not just for academic success but more broadly including for a child’s mental health and happiness.

In this special episode of the Child of our Time Podcast, Professor Yvonne Kelly is joined by Jonathan Douglas, CEO of the National Literacy Trust and researcher Christina Clark, also from the  Trust. They discuss important new evidence about the benefits of reading for individual children and in addressing social inequalities.

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