Tag Archives: Young people

Teenage obesity and bowel cancer risk

Bowel cancer is the third most common cancer among men worldwide, with nearly 1.4 million new diagnoses each year. Links with obesity in adulthood are fairly well established with what appears to be a rise in risk with increasing body mass index. The link is significantly stronger for men than it is for women. Much less is known about potential causes at earlier stages of life, especially adolescence, as Professor Scott Montgomery from UCL explains.

Adolescence marks the transition from childhood to adulthood and is a period of accelerated growth, especially for men. We wanted to look at whether obesity, or even just excess weight, during the teenage years increase the likelihood of colorectal cancer later in life?

Asking men diagnosed with bowel cancer what they weighed as teenagers is not a reliable source of data. What we needed to examine this question robustly was a large sample of men who were accurately measured in their youth and are now sufficiently old for a significant number to have developed bowel cancer.

One such group is men who experienced compulsory Swedish military conscription assessments. Around a quarter of a million young men aged around 18 years were assessed for conscription between 1969 and 1976. After excluding those with errors in the original measurements and excluding men with pre-existing medical conditions gave us a sample of just under 240,000 – equivalent to 8 and half million person years of data.

The men’s height and weight was measured by trained personnel during the conscription examination. From these data body mass index (BMI) or kg/m² was calculated and those numbers were put into five groups – underweight (BMI of less than 18.5), normal (BMI of 18.5 to 24.9), lower overweight (BMI of 25 to 27.4), upper overweight (BMI of 27.5 to 29.9) and obese (BMI of over 30).

A blood test was also taken and tested for signs of higher levels of inflammation, which can signal diseases processes relevant to bowel cancer risk.

Cancer diagnosis

Over an average of 35 years following conscription, 885 of the men were diagnosed with bowel cancer, comprising 501 cases of colon cancer and 384 cases of rectal cancer.

Men who had been underweight in adolescence had a slightly lower risk of a colorectal cancer diagnosis than normal weight men. Lower overweight men had a non-statistically significant higher risk, upper overweight men had a statistically significant 2.08-fold higher risk and obese men had a 2.38-fold higher risk.

Men, who had suffered high levels of late adolescent inflammation, were found to be at a 63% higher risk of being diagnosed with bowel cancer than those with normal levels. The link between BMI and a diagnosis was independent of inflammation levels, suggesting adolescent BMI may be operating in a different way and through mechanisms other than the inflammation detected during adolescence.

The average age at the end of follow-up was 53.9 years, so our analysis did not look at any changes in late adulthood. It seems unlikely, though, that the upper weight groups would suffer less in later years.

It was also impossible to account for whole life measures of BMI and inflammation and so we are not able to comment on whether the strong association between adolescent BMI and bowel cancer could be mitigated by weight loss during adulthood. It is, however, plausible that it is the total duration of exposure to high BMI or inflammation that brings the increased risk rather than exposure at a specific age. High BMI or inflammatory processes already present during adolescence may persist for many years into adulthood.

It is also important to stress that the findings do not necessarily apply equally to women. Certainly, other studies have shown the associations between BMI and inflammation and bowel cancer are weaker among women than men.

Robust study

All that said, this is a robust, important study based on good quality measurement and a lengthy time frame. At a time when increasing adolescent obesity in the United States, for instance, appears to be being followed by an increasing incidence of bowel cancer among young adults, it contributes to the case for further work to be undertaken with some urgency.

What our research does suggest is a graded association between adolescent inflammation and bowel cancer and an even stronger association between adolescent BMI and the risk of bowel cancer in men. We have notable evidence of a link between these exposures at a particularly vulnerable stage of development and the later incidence of bowel cancer.

More work needs to be done, particularly to clarify how inflammation and BMI act or interact to affect an increased risk of bowel cancer. Further research is also needed to disentangle these factors from other risks both in adolescence and later life.

Further information

Adolescent body mass index and erythrocyte sedimentation rate in relation to colorectal cancer risk is research by Elizabeth D Kantor, Ruzan Udumayan, Lisa B Signorello, Edward L Giovannucci, Scott Montgomery and Katja Fall and is published in the journal, Gut.

Photo credit: Marina Lobanova

Are children becoming obese earlier?

Are children becoming obese at a younger age compared with the generations before them? New evidence from a research team at CLOSER, making use of the UK’s Cohort Studies, indicates they are. One of the team, Professor Rebecca Hardy from UCL, spoke to Child of our Time about the research.

How has the age-related process of overweight or obesity development changed over time? Coordinated analyses of individual participant data from five United Kingdom birth cohorts, is research by William Johnson,  Leah Li,  Rebecca Hardy and Diana Kuh, and is published in PLOS Medicine.

Child of our Time podcasts are produced by Research Podcasts.

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Get up, get out, get active!

Just what are the long term effects of being a couch potato as a youngster? New research using the  1970 British Cohort Study shows we may reap what we sow if we don’t switch off the television or the Playstation and get ourselves and our kids off the couch and active. Dr Mark Hamer from UCL spoke to Child of our Time about the research.

“Childhood correlates of adult TV viewing time: a 32-year follow-up of the 1970 British Cohort Study”, by Lee Smith, Ben Gardner and Mark Hamer of UCL’s Department of Epidemiology and Public Health. It will be published in a future issue of the Journal of Epidemiology and Community Health.

Child of our Time podcasts are produced by Research Podcasts.

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Middle-aged couch potatoes ‘planted’ 30 years earlier

Parents should routinely switch off the TV and take young children out for a walk or some other exercise in order to increase their chances of growing up to be fit, healthy adults, new research suggests.

And if it isn’t feasible to go outside, children could perhaps be encouraged to play interactive video games that involve physical activity.

Researchers at University College London have reached these conclusions after comparing the TV viewing habits of more than 6,000 British people at age 10 and age 42.

The study revealed that children who watched a lot of TV at age 10 were much more likely to spend more than three hours a day in front of the screen at age 42 than those who had watched relatively little television in childhood.

Eighty-three per cent of the 1,546 cohort study members who reported watching more than three hours of TV at 42 had also watched TV “often” at age 10.

The study also showed that 42-year-olds who watched TV for at least three hours a day were more likely to be in only “fair” or “poor” health and to report that they were either overweight or obese.

They were also more likely to have had fathers who were overweight and in routine or manual jobs at the age 10 survey. The sons and daughters of manual workers were, in fact, twice as likely as managers’ children to watch more than three hours of TV a day at 42, even after their own educational qualifications had been taken into consideration.

The researchers analysed information collected by the British Cohort Study, which is following the lives of people born in England, Scotland and Wales in the same week of 1970. The cohort study is managed by the IOE’s Centre for Longitudinal Studies (CLS) and is funded by the Economic and Social Research Council.

“The problems that we have identified are not experienced exclusively by working-class families,” Dr Mark Hamer, one of the UCL researchers, will tell the CLS research conference in London today (March 16).

“However, parents from a lower socio-occupational class are more likely to be physically active at work and may compensate for this by spending more time sitting down during their leisure hours. Their children may then model their mothers’ and fathers’ leisure activity patterns.

“It is important that children keep active. And if they can be encouraged to participate in sports, so much the better.”

Previous research has suggested that parental participation in physical activity may be a predictor of childhood activity levels. The UCL study is, however, believed to be the first to use a large, representative birth cohort to identify childhood factors that are associated with television viewing habits in middle age.

“Our work indicates that parents’ health-related behaviours may at least partly influence children’s TV viewing habits more than three decades later,” Dr Hamer says. “This has important implications for policy and practice.

“It suggests that interventions to reduce passive TV viewing time should target children and their parents. Such initiatives could not only help today’s children but help to reduce passive TV viewing in future generations.

“That could be extremely beneficial as research has also shown that TV viewing is associated with other health-risk behaviours, such as the consumption of energy-dense foods and cigarette smoking. Prolonged TV viewing has also been linked to type 2 diabetes and cardiovascular disease.”

The paper that will be presented at the CLS conference is “Childhood correlates of adult TV viewing time: a 32-year follow-up of the 1970 British Cohort Study”, by Lee Smith, Ben Gardner and Mark Hamer of UCL’s Department of Epidemiology and Public Health. It will be published in a future issue of the Journal of Epidemiology and Community Health.

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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.

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Further information and links

Read a full transcript of the presentation

National Diet and Nutrition Survey

Alcohol and adolescence: who’s drinking age 11?

Who is drinking alcohol at age 11? And what are the links with parents’ and friends drinking habits? See the slides and listen to Professor Yvonne Kelly talk at an ESRC Centre for Lifecourse Studies Policy Seminar about her research, Alcohol and adolescence: exploratory drinking in 11 year-olds, which makes use of data from the Millennium Cohort Study.

Photo credit: Jes 

 

 

Understanding ethnicity in the battle against obesity

One in five children in Reception class (age 4-5) at school is either overweight or obese according to the most recent figures from Public Health England. By the time they go into year 6 (age 10-11), the figure rises to one in three. Over time our children are becoming increasingly overweight and it’s a tide that parents, teachers, health professionals and policy makers are struggling to stem. But are there children from particular ethnic and cultural backgrounds who are at greater risk of becoming obese? If so, would a better understanding of who those children are help in the battle against obesity? Afshin Zilanawala has been exploring the links between a child’s weight or BMI and their ethnicity and asking which factors might need further consideration when it comes to tackling the problem.

Healthy eating initiatives like the recent NHS Change for Life Campaign which seeks to make families healthier and happier will hopefully play a role in getting children to eat the right things and be more active. All well and good if the messages are getting through loud and clear. But what if they’re not? And what if the reasons for that are somehow related to a child’s ethnicity?

There have been very few detailed studies of the links between a child’s ethnicity and their weight, something highlighted in the National Obesity Observatory’s 2011 report Obesity and ethnicity. However, a growing body of evidence is showing that children from certain ethnic backgrounds are at greater risk of obesity than their white peers.

So what factors are at play and what can we learn that might help overcome any cultural and social barriers that might stop these important messages getting through?

Key information such as what language is spoken at home, family routines and diet have been missing from the analysis. That combined with a tendency (partly because of a lack of available data) to lump people from very different ethnic backgrounds together has left a real void when it comes to quality evidence that could be used to develop and implement initiatives and interventions that could work.

Scrutinising family and cultural routines

Our research has gone some way to fill that void. We wanted to scrutinise more closely the cultural and family routine factors that might be linked to obesity across and within ethnic groups. We were able to do this making use of the very rich data available in the Millennium Cohort Study, which follows the lives of nearly 20,000 children.

When the children were 5, their height and weight were measured and a parent (usually the mother) answered questions about the family’s circumstances, their cultural traditions and routines.

Things that were taken into consideration about the mother were: whether the mother was working, whether she was a single parent, income and qualifications and her BMI. For cultural traditions we looked at the language spoken at home, and whether the mother was first, second or third generation immigrant. And for family routine and nutrition, we focused on the child’s bedtime and how much fruit they ate each day.

All those things were then looked at to see whether they were linked in any way with a child’s propensity to be overweight or obese at age 5.

Obese and overweight

What we found was that those children from a Black African, Black Caribbean and Bangladeshi background were around twice as likely as their white peers to be obese. Black Caribbean children were the most likely to be obese and Black African children were the most likely to be overweight. Pakistani children, by contrast, were the least likely to be overweight or obese and, indeed, 40% less likely to be obese than their white counterparts.

Other findings included:

  • Pakistani, Bangladeshi, Black Caribbean and Black African children lived in the poorest households
  • Mums of Indian, Bangladeshi and Pakistani children were most likely to speak a language other than English at home
  • Bangladeshi children were most likely to go to bed after 9pm and least likely to eat any fruit in a day
  • Mums of Black African children were most likely to have a high BMI

What emerged when we drilled down further, however, was that none of the factors we took into consideration could completely explain or account for the ethnic disparities or differences in the likelihood of a child being overweight or obese. That doesn’t mean that we conclude that diet and routine aren’t important, but it does indicate that there may be other important influences at play or that more detailed examination of children’s diet is needed if we are to get a better understanding of these disparities.

It is also clear to us that grouping together children from different backgrounds in research examining these important questions simply does not manage to bring to light which groups of kids are most at risk.

The British Nutrition Foundation has said it is “essential to encourage healthier eating and lifestyle habits from an early age, particularly within ‘at risk’ ethnic groups” and that “acquiring a better understanding of their dietary habits, including aspects of their traditional diets, can help health professionals and educationalists to recognise the needs of these groups and to support them to make healthier food choices”. This is something our research certainly reinforces.

Our work also indicates that obesity-related services for those ethnic group children most at risk could be a step in the right direction. Given that the Government says it wants to see a sustained downward trend in the level of excess weight in children by 2020, initiatives and interventions that take these things into consideration could start tipping the scales more in favour of that ambition being achieved.

What might work?

A report for the Departments of Health and Education back in 2008 made some interesting suggestions about approaches that could work. These included:

  • Encouraging exercise in culturally appropriate activity; eg traditional/contemporary dance for girls; parents who prioritise schooling may react positively to after school clubs
  • Focus on making traditional meals healthier; eg olive oil for ghee or palm oil
  • Get approval/help of key community leaders to champion exercise/ healthy diet
  • Engage with elders to remove assumption that a fat child is a healthy child
  • Encourage children to talk to mothers about issues where mother has little English

Common sense suggestions like these, which are based on observational research, are likely to be useful to local authorities across the UK now tasked with tackling obesity in their communities.

But it is rigorous, robust academic evidence made possible by longitudinal studies like the Millennium Cohort Study that will provide us with the nuanced picture that will help us really get under the skin of the problem of obesity. Focused, informed policies and interventions that emerge from this evidence stand the greatest chance of success.

Further information

This blog is partially based on Race/ethnic disparities in early childhood BMI, obesity and overweight in the United Kingdom and United States, research by Afshin Zilanawala, James Nazroo, Yvonne Kelly, Amanda Sacker, Pamela Davis-Kean and Sharon Simonton published in the International Journal of Obesity.

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Poor and obese: why poorer adolescents are more likely to be overweight

What are the links between poverty and obesity? And are policy initiatives aimed at getting children to consume less fizzy drinks and sugary snacks enough to tackle the problem? Professor Amanda Sacker looks at the picture for 11 year-olds in our latest Child of our Time Research Talk recorded at a recent ESRC International Centre for Lifecourse Studies policy seminar.

Photo credit: Matthew Kenwrick

 

How racism can damage our children’s development

There is now a compelling body of evidence linking families’ experiences of racism with poorer health and development in children. That’s according to Professor Yvonne Kelly, who believes there’s a clear argument for putting racism firmly in the mix when it comes to tackling the things that impact negatively on our children’s happiness and well-being, including obesity.

Professor Yvonne Kelly talks to Child of our Time Editor, Chris Garrington about research looking at mothers’ experiences of racism and how it affects their children.

 

Racism rise would be bad for the kids

A range of anti-racism initiatives and policies have been put into place in recent years by successive Governments in the UK. But could those efforts be undermined as we move into a period where it seems “anti-immigrant” sentiment and rhetoric is on the increase?

With one in three people in Britain describing themselves as being very or a little racially prejudiced, according to a recent British Social Attitudes Survey, what might be the consequences of any rise in racist attacks whether physical or verbal on people from an ethnic minority background, in particular children? Professor Yvonne Kelly blogs on recent research showing that racism needs to be firmly in the mix of things to tackle when policymakers are trying to ensure the health and happiness of the UK’s children.

From negative and inaccurate stereotypes and behaviours to open threats, insults and physical violence, there is a growing body of evidence of the links between racist behaviours like these and poor mental and physical health in children and young people.

Two pieces of research from the ESRC-funded International Centre for Lifecourse Studies have been looking at the impacts of racism on the social, emotional and physical development of children and find links between the racism they and their parents experience and behavioural problems, poor school performance and obesity.

In a research paper for Social Science and Medicine, the research team at ICLS looked at more than 120 studies (predominantly in the US) which explored the relationship between reported racism and health and wellbeing for children and young people.

Health outcomes 

Of the 461 health-related outcomes reported in these studies, things like depression and anxiety were most commonly reported, with statistically significant associations with racial discrimination found in 76% of outcomes examined.

Racial discrimination also impacted heavily on self esteem and resilience and was closely associated with behaviour problems, poor well-being, and issues around pregnancy and birth such as going into labour early and low birthweight.

The studies showed a strong link also between racial discrimination and delinquent behaviour and risky behaviours including drinking, smoking and drug taking.

Although links with physical health were less prominent,researchers put this down to the fact that there is likely to be a delayed onset of issues such as obesity, high blood pressure and other chronic illnesses, which often become evident long after damaging exposure to racism occurs.

Interestingly, preschoolers’ mental health appeared to be less badly affected than that of  older children. The researchers say this could be down to the ability of carers to effectively buffer children of this age from the detrimental effects of racial discrimination.

Mothers and racism

A second piece of research, the first of its kind, looked at how mothers’ experiences of racism affected the physical and mental health of more than 2000 5 year-olds in the Millennium Cohort Study.

When the children in the study turned 5, all mothers were asked about racist attacks in their neighbourhood including questions like:

 “How common are insults or attacks to do with someone’s race or colour?”

Mothers from ethnic minority groups were asked four questions about their own experiences of racism and discrimination over the previous 12 months:

“How often has someone said something insulting to you because of your race or ethnicity?”

“How often have you been treated unfairly just because of your race or ethnicity?”

“How often has a shopkeeper or salesperson treated you in a disrespectful way just because of your race or ethnicity?”

“How often have members of your family been treated unfairly just because of their race or ethnicity?”

The children’s height and weight were measured and mothers were asked to fill in a special questionnaire designed to pick up on difficulties such as hyperactivity and attention problems. Their verbal and problem-solving skills were also assessed in a range of tests.

Ethnic minority groups looked at in the research were:

  • Indian (416)
  • Pakistani (716)
  • Bangladeshi (294)
  • Black Caribbean (348)
  • Black African (362)

About 12% of mothers reported that racist insults or attacks were fairly/very common in their residential area. 23% of mothers reported that they had experienced verbal insults in the previous 12 months, 20% reported having experienced unfair treatment due to race or ethnicity, 17% reported experiencing disrespectful treatment from shop staff and 23% reported that a family member had been treated unfairly due to their race or ethnicity.

Bangladeshi mothers were most likely to perceive problems to do with racism in their residential areas, while Black Caribbean and African mothers were most likely to report unfair treatment, disrespectful treatment in shops and unfair treatment of family members.

Children of mothers who had experienced racism at first hand were around one and a half times more likely to be obese than children of mothers who had not.

Children living in areas were the mothers described racism as common were more likely to have social and emotional difficulties and performed worse in certain tests.

Conclusion and key points 

There is now a compelling body of evidence linking racism with poorer health and development in children, something which has long-term implications for their well-being.

Given the public health  and policy drives to tackle obesity, there’s a clear argument for not simply focusing on diet, physical activity and parenting, and for putting racism firmly in the mix.

Research links and information

A systematic review of studies examining the relationship between reported racism and health and wellbeing for children and young people is by Naomi Priest, Yin Paradies, Brigid Trenerry, Mandy Truong, Saffron Karlsen and Yvonne Kelly. It is published in Social Determinants of Child Health, a Special Issue of Social Science & Medicine.

Associations between maternal experiences of racism and early child health and development: findings from the UK Millennium Cohort Study is a research report by Yvonne Kelly, Laia Becares and James Nazroo. It is published in the Journal of Epidemiology and Community Health.

This research was produced as part of an ESRC-funded project, Disparities in Children’s Health and Behavior: The Importance of Race/Ethnicity in the UK and US.

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