Tag Archives: Teenager

Sugar-coating the childhood obesity problem

Child obesity figures appear to be on the rise again, causing much concern after earlier signs they had levelled off.  The proportion of  10- and 11-year-olds who were obese in 2015-16 was 19.8 percent, up 0.7 percent on the year before. There was a rise of 0.2 percent among four- and five-year-olds. The announcement comes as researchers at the ESRC International Centre for Lifecourse Studies at UCL have been looking in detail at how and when children become overweight. The team has also been asking whether children who are overweight are more likely to go on to smoke and drink alcohol and if their mental health suffers as they become adolescents. Yvonne Kelly explains the research findings, and considers their implications for the Government’s recent strategy for tackling the childhood obesity epidemic.

The Government’s much-awaited and much-debated childhood obesity strategy was published in August. In the end, it was less comprehensive than had been anticipated, less draconian too. It focuses on two things – reducing sugar consumption and increasing physical activity. But will it be effective in reversing this worrying obesity trend among our children?

It’s fair to say we don’t fully understand what things influence whether, when and why a child might become overweight. Research to date has shown three distinct weight pathways for children: a healthy BMI throughout childhood; becoming overweight during childhood and being overweight/obese throughout childhood.

Previous research has also shown that the child’s mother’s weight, smoking in pregnancy, mental health and other social and economic factors have some link to childhood obesity. But the evidence is far from complete and, where a child’s own mental health is concerned, it’s not at all clear which way the association works.

To try to get a clearer picture of all these things, our research looked at the BMI paths of the participants in the Millennium Cohort Study, which has tracked the lives of nearly 20,000 children born between 2000-2002. We used data collected at birth, 9 months, age 3, 5, 7 and 11.

Once we had established who was on which BMI path, we were able to look at what factors were at play in their lives and to see whether a tendency to overweight and obesity was an indication that a child would go on to face mental health difficulties in early adolescence or start smoking and drinking.

Four pathways to obesity

The BMI data for the 17,000 children we were able to look at for our study showed four distinct groups of children. More than 80 per cent of them stayed on an average non-overweight path throughout their childhood – we call it the ‘stable’ path. There was a small group (0.6 percent) of children who were obese at age 3 but were then in the stable group by age 7. We call them the the ‘decreasing’ group. There was a ‘moderate increasing group’ (13.1 percent) where children were not overweight at age 3 but whose BMIs increased throughout childhood into the overweight (but not obese) range. Finally we had a ‘high increasing’ group of children (2.5 percent) who were obese at age 3 and whose BMIs continued to increase.

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Girls were 30 percent more likely to be in the ‘moderate increasing’ group than boys and were half as likely to be on the ‘decreasing’ path. Indian, Pakistani and Black African children were up to two times more likely to be on the ‘moderate increasing’ path whilst Pakistani, Black Caribbean and Black African children were up to three times more likely to belong to the ‘high increasing’ group.

The wealthiest children were least likely to be in the ‘moderate increasing’ BMI group and children of mums who smoked during pregnancy were up to two times as likely to belong to increasing BMI groups. Children with overweight mums were most likely to be on the moderate and high increasing paths.

Children on the moderate and high increasing paths were less likely to have regular family routines – they were more likely to skip breakfast or have non-regular bedtime schedules. Interestingly, however, no strong links emerged with some of the things more readily linked with childhood obesity such as sugary drinks and snacks, watching TV and lack of physical activity such as sports, the main focus of the newly published childhood obesity strategy.

Overweight factors

So it seems quite a large range of factors influence the likelihood of a child becoming overweight or obese over the first decade of their life. On top of this, being overweight or obese would also seem to point to a less happy and fulfilling early adolescence and a tendency to explore risky behaviours like smoking and drinking.

Although our research did not show a clear link with sugary drinks and snacks, there are nevertheless some compelling arguments for reducing the sugar intake of our children. These are not only related to problems of obesity, but to wider issues including the major issue of tooth decay and associated emergency hospital admissions. There is also increasing evidence of the ‘addictive’ nature of sugar with research suggesting that it stimulates a sort of ‘reward path’ in certain centres of the brain meaning that the more we have the more we want. It has been shown that people who reduce their sugar intake tend to crave it less.

Where sugar taxes have been introduced in other countries (Mexico, France, Denmark, South Africa amongst others), the intervention has been shown to help reduce the consumption of sugary drinks. As yet, there is no evidence that it helps reduce BMI and tackle obesity, but it’s argued it will take time for us to see an effect on whole populations.

Disadvantaged families

It is hard to predict how much impact the voluntary rather than mandatory reduction in sugar content of drinks and snacks agreed in the strategy will have. As for the sugar tax that will be introduced in two years’ time, there remain concerns that disadvantaged families more likely to purchase and consume sugary goods than their better off counterparts will be hardest hit. Policy makers will need to think hard about how any negative consequences of this might be counteracted.

Our research shows clearly that when it comes to the likelihood of a child becoming overweight or obese in the first decade of their life, there are many more influences than just sugar. Those influences are at play in families even before our children are born.

Helping pregnant women to stop smoking and maintain a healthy weight, making sure all young children have healthy eating and sleeping routines would seem to be key, together with targeted support for the ethnic and social groups identified as being most at risk.

Further information and resources

BMI development and early adolescent psychosocial well-being: UK Millennium Cohort Study is research by Yvonne Kelly, Praveetha Patalay, Scott Montgomery, and Amanda Sacker. The work, published in Pediatrics, is funded by the Economic and Social Research Council.

Media coverage

Photo credit: Kim Stromstad

Early puberty: a question of background?

New research examining the connections between early puberty in girls and their socioeconomic and ethnic backgrounds is being presented to an international audience of researchers in Germany today.

Early puberty in 11-year-old girls: Millennium Cohort Study findings is work led by Child of our Time editor Yvonne Kelly using information on 5,839 girls from the Millennium Cohort Study.

The findings, presented at the Society for Longitudinal and Life Course Studies 2016 conference in Bamberg indicate clearly that socioeconomic and ethnic disparities are apparent in the UK and are important for all those interested in the short and long term implications for early puberty on women’s health and well being.

Girls growing up – questions of early puberty

The early onset of puberty in girls has been linked with better bone health in older women, but it is also associated with a host of negative outcomes including teenage pregnancy and serious ill health in mid-life. With girls over the last few decades starting their periods earlier and earlier, this is a real cause for concern. A better understanding is needed of who is affected and how if this trend is to be reversed and the long-term health of girls and women is to be secured. Researchers at the ESRC International Centre for Lifecourse Studies at UCL have investigated whether a girl’s socioeconomic background or ethnicity are associated with early puberty and have looked in detail at more commonly supposed links with weight and stress. Yvonne Kelly explains more.

Sexual activity whilst still young, teenage pregnancy, mental health problems, heart disease and breast cancer later in life are just some of the things linked to early puberty in girls. Over the last few decades, girls have started their periods much earlier with the average age falling from puberty has age falling to 12.9 years in 2015.

This research is the first to look over time at whether and how a girl’s social and economic circumstances and her ethnicity might be linked to the early onset of puberty. We suspected that any link that did emerge would, most likely, be explained away by other factors such as being overweight or suffering from stress.

Using information on 5,839 girls from the Millennium Cohort Study, which has been tracking the lives of nearly 20,000 children born at or around the start of the century, it was possible to know, at age 11 whether they had started their period or not.

Details of their birth weight, ethnicity, family income when they were aged 5 and height and weight when they were 7 were also available. This rich information gathered across 11 years of the girls’ lives really enabled us to put together a detailed picture over time of how these factors come together to influence the early onset of puberty.

The girls’ mothers completed questionnaires any social or emotional problems their daughter might be facing, and their own mental health.

Puberty facts and figures

Nearly one in ten of the girls, a total of 550, had started their period at age 11, with girls from the poorest families twice as likely as their most well-off peers to have done so (14.1 per cent v 6.8 per cent). Those from the second poorest group were also nearly twice as likely to have started their period.

Indian, Bangladeshi and Black African girls were most likely to have started their period at age 11, with Indian girls three and a half times more likely than their White counterparts to have done so.

Other factors

On average, girls who were heavier at age 7 and suffered stress in early childhood were more likely to have begun menstruating. Those who had started their periods early also tended to have mothers with higher stress levels, were from single parent families, and tended to have had some social and emotional difficulties themselves.

However, even when we took all these things into account, girls from the poorest and second poorest groups were still one and a half times more likely to have started their periods early.

As far as ethnicity was concerned, income, excess body weight and stress accounted for part or all of the differences in most cases. Interestingly, though with most Indian girls coming from more advantaged backgrounds than their White peers, the likelihood of them having started their period was not explained after we took all the above factors into account.

Lived experiences

Our findings highlight the different lived experiences of ethnic minority groups in the UK: for example Indians are relatively advantaged whereas Pakistanis tend to be materially disadvantaged, Bangladeshis and Black Africans are materially and psychosocially disadvantaged and have a tendency to be overweight compared with the majority ethnic group. They also demonstrate the complex and potentially opposing factors at play for the onset of puberty.

All that considered, we can say with considerable confidence that socioeconomic and ethnic disparities are indeed apparent in the UK. Given the short and long term implications for early puberty on women’s health and well being, improving our understanding of these underlying processes could help identify opportunities for interventions with benefits right across the lifecourse, not just for the girls in our study, but for future generations.

It was also encouraging to note that in the decade or so covered by the data we used, there appears to have been no further decline in the average age that girls begin puberty.

Early puberty in 11-year-old girls: Millennium Cohort Study findings is research by Yvonne Kelly, Afshin Zilanawala, Amanda Sacker, Robert Hiatt andRussell Viner and is published in Archives of Disease in Childhood.

Photo credit: Afla

Who are the 11 year old drinkers?

The number of young people who say they drink alcohol has recently fallen. But the teenage years are still the time most of us start drinking. Drinking can be linked to other types of risky adolescent behaviour and, later in life, alcohol remains a major risk factor for illnesses such as heart attacks, cancer and diabetes. Most research to date has focused on the later teenage years, but a new study published in BMC  Public Health has taken a close look at children in early adolescence. Professor Yvonne Kelly at the ESRC International Centre for Lifecourse Studies at UCL examines the circumstances in which children first explore alcohol and what this can tell public health professionals keen to counter the most damaging effects.  

The Department of Health guidelines are clear; children aged 16 or less should not drink alcohol. But they do and many parents fear absolute prohibition will lead to secret drinking and a loss of trust in the relationship. It would appear to be common sense, too, that a child drinking a small amount of watered-down wine with a family meal would be likely to develop quite different later adolescent behaviours to a child swigging vodka with friends in a bus shelter. Common sense it might be, but there has been little robust research around this.

The broad aim of our research was to examine influences on the emergence of exploratory drinking at the start of adolescence. We focused on two specific questions:

  1. Are parents’ and friends’ drinking important influences on drinking among 11 year-olds?
  2. What is the role of perceptions of risk, expectancies towards alcohol, parental supervision and family relationships on the likelihood of 11 year-olds drinking?

We made use of the detailed and rich data available in the Millennium Cohort Study (MCS), which has followed the lives of nearly 20,000 children born between 2000-2002.

Drinking habits

At age 11, just under 14% of MCS children said they drank alcohol. Based on their own reported drinking frequency, parents were grouped into three categories: non-drinkers, light to moderate drinkers and heavy or binge drinkers. Around 20% of mums and 15% of dads were non-drinkers. Around 60% of mums and dads were light or moderate drinkers. About a quarter of dads and just over a fifth of mums were heavy or binge drinkers. When asked whether their friends drank, 78% of MCS children said “no”.

The children were also asked about other risky behaviours such as smoking or truanting and what they felt about their family. These factors were taken into account to enable us to focus in on the effect of parents’ or friends’ drinking.

Compared to children whose mums did not drink, children whose mums were light or moderate drinkers had a 60% increased risk of drinking at 11, while those whose mums were heavy or binge drinkers had an 80% increased risk. A father’s drinking appeared to have about half as much impact, regardless of whether he was a light to moderate or heavy/binge drinker. Children who said their friends drank were more than four times as likely to drink themselves as those children with friends who didn’t drink.

Home life and perceptions of alcohol

When we looked at home life, predictably those children who reported being happy were less likely to drink than those who reported frequent family battles. Where there were low levels of parental supervision combined with a dad who drank heavily, the risk of the child drinking was, again, higher.

A child’s view about the harms of alcohol also seemed to be an important factor. The more dangerous a child thought alcohol to be, the less likely they were to drink. Children who did not see drinking alcohol as a risky activity and who also had a heavy drinking mum were much more likely to be drinking alcohol at 11.

It is not possible to make statements regarding cause and effect with this sort of study, but the numbers do show us a strong association between 11 year-olds drinking and their friends’ and mothers’ behaviour. Family relationships, perceptions of risk and expectations regarding alcohol are important, too, as are some more general characteristics of the family unit.

So, what does this tell us about the risks of drinking at 11 and how to counter those risks? The fact that likely causes of early drinking are multiple, means that counter measures need, similarly, to be aimed at a number of different aspects of a child’s life. One size will not fit all.

Advice, information and guidance

Children certainly need to have a better understanding of the risks involved in drinking. Schools and parents are clearly well placed to provide the best advice, information and guidance to children of this age, but these robust new findings can play an important role in helping to shape the focus of those discussions.

Whilst the vast majority of children at the age of eleven are yet to explore alcohol, investigating in more detail the context in which children drink – who they drink with, where, when, what they drink and how they acquire alcohol – could help inform effective policy and alcohol harm prevention strategies to mitigate the risk associated with drinking as a young person.

Public health policy should take all these factors into account, driving measures that would address parents and peer groups, popular perceptions, marketing and advertising, pricing, availability and the enforcement of age restrictions.

Further information

What influences 11-year-olds to drink? Findings from the Millennium Cohort Study is research by Yvonne Kelly, Alice Goisis, Amanda Sacker, Noriko Cable, Richard G Watt and Annie Britton and is published in BMC Public Health.

  • Read the press release and access contact details if you are a member of the media
  • Listen to Yvonne’s talk on the research at a recent ICLS Policy Seminar
  • Find out about forthcoming ICLS Policy seminar on Tuesday, 21 June 2016, focusing on what evidence longitudinal/lifecourse studies can bring to the current debate on “safe” drinking levels and what drives people to start, stop or cut back on drinking. Email icls@ucl.ac.uk for more information and to be added to the mailing list.

Photo credit: Jes

 

Why poorer children are at greater risk of obesity

Obesity may be the biggest public health crisis facing the UK today. Levels have risen more than three fold since 1980. Being obese makes you vulnerable to a range of health risks. Being an overweight child makes it more likely you will become an obese adult. And you are much more likely to be an overweight child, if you come from a poor family. If current trends continue, half the population of Britain could be obese by 2050. Early intervention is the most effective way to break this cycle. And that requires a better understanding of why children become overweight. A new study by a team at the ESRC funded International Centre for Lifecourse Studies in Society and Health at UCL and LSE makes clear the scale of the problem and points to some crucial factors likely to lead less-well-off children to gain excess weight, as co-author Professor Yvonne Kelly explains.

A link between poverty and childhood obesity has been found in many developed countries. Intuitively, it seems likely this link is the result of poorer parents not being able to afford healthier food, like fruit, or outings involving exercise for their children. It could also be that those parents know less about healthy lifestyles and that they themselves eat less healthily and exercise less. But intuition is an insufficient basis for the scale of intervention required. This study is the first attempt to examine and compare in detail why children in poorer families are more likely to be overweight.

Our data comes from the Millennium Cohort Study (MCS). This tracks nearly 20,000 families from across the UK. We used measurements made when the children were aged 5 (when just entering primary school) and 11 (the point at which they leave primary school and are on the cusp of adolescence). We used standard definitions for ‘obese’ and ‘overweight’.

‘Stark’ link between poverty and obesity

The first thing we found was that the link between relative poverty and childhood obesity is stark. At age 5, poor children were almost twice as likely to be obese compared with their better off peers (6.6% of children from families in the poorest fifth of the sample were obese while the figure for the richest fifth is just 3.5%). By the age of 11, the gap has widened- nearly tripling (7.9% of the poorest fifth are obese; for the best-off, the figure is 2.9%).

Given that obesity is linked to the development of numerous chronic diseases and that there is evidence overweight and obese children are less likely to grow into economically and socially successful adults, this is a significant burden to be borne by the children of the less-well-off. And unless we can weaken the link our chances of reversing the overall obesity trend are much reduced.

Potential causes of that link

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

To measure the degree to which the mother followed a healthy life-style 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 the mother was herself overweight or obese. To assess the impact of physical behaviour, we compared the frequency of sport or exercise, active play with a parent, hours spent watching TV or playing on a computer, journeys by bike and the time that children went to bed. We compared dietary habits via data on whether the child skipped breakfast and on fruit and sweet drink consumption.

Multiple factors

What we found was that a lot of these factors were relevant. Maternal behaviour in early childhood was certainly important. Markers of ‘unhealthy’ lifestyle here could mean as much as a 20% additional risk of obesity for a child. Measures of physical activity and diet were also relevant at both 5 and 11 years of age, as were early bedtimes and fewer hours in front of the TV or games console. Skipping breakfast and eating more fruit were factors at 5 but less significant at 11. Doing sport more frequently played a more important and protective role at age 11 than at age 5.

Further examination of the differences between the children aged 5 and aged 11 revealed that poorer children aged 5 were much more likely to gain excess weight up to age 11 than richer children. The earlier certain lifestyle factors can be challenged, therefore, the greater the chance of positive impact.

Multiple responses

Assuming that income inequality is not going to disappear, we can only tackle ‘inherited’ obesity via the lifestyle choices that tend to go with lower incomes. Early intervention with mothers clearly has huge potential. And evidence from our work suggests that this should start before birth or even conception. It is clear, too, that campaigns to encourage family physical activity and healthier diets would help.

The Government is already trying to persuade families to eat more healthily and take more exercise. But these efforts are widely targeted and their effectiveness only broadly assessed. Our analysis has already suggested better targeting. More research should be undertaken to narrow the aim and increase effectiveness still further.

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.

Photo credit: Playing on the computer,  John Watson

 

 

What teenage girls eat

Teenage girls have the poorest diets of all according to the National Diet and Nutrition Survey with less than one in ten girls eating the recommended five-a-day fruit and vegetables.

At an ESRC International Centre for Lifecourse Studies Policy Seminar, researcher Laura Weston presents preliminary evidence from NatCen Social Research on adolescent girls’ nutrient intake and the factors that influence it.

Photo credit: Magdalena O

Further information and links

Read a full transcript of the presentation

National Diet and Nutrition Survey