One in five ‘children of the new century’ obese by age 11

27 November 2014

One in five children born in the UK at the beginning of the new century was obese by the age of 11, a new study shows.

A further 15 per cent of the 13,000 children being followed by researchers at the Institute of Education, London, were found to be overweight.

The latest findings from the Millennium Cohort Study (MCS) will add to public concern over child obesity in the UK.

Children who are overweight or obese face an increased risk of many health problems, including asthma, cardiovascular disease and type 2 diabetes. Childhood overweight and obesity are also associated with psychological problems such as low self-esteem and depression.

The IOE analysis, which is to be published tomorrow (Friday, November 28), points out that the proportion of ‘children of the new century’ who were classified as obese jumped from 13 per cent at age 7 to 20 per cent at age 11.

“The number of children who were an unhealthy weight was significantly greater at age 11 than in previous MCS surveys,” said Dr Roxanne Connelly, who analysed the data. “The overall proportion who were either overweight or obese rose from 25 per cent at age 7 to 35 per cent at age 11.”

By age 11, boys in the MCS had reached an average height of 1.46 metres (4ft 9ins), while girls were slightly taller at 1.47 metres (4ft 10ins). Girls also weighed slightly more, with an average weight of 42kg (6st 9lbs) compared to 41kg (6st 6lbs) for boys.

The prevalence of overweight and obesity varied significantly by country in the UK. Forty per cent of 11-year-olds in Wales and Northern Ireland were overweight or obese compared to 35 per cent in England and 33 per cent in Scotland.

There was a clear link between children’s weight at age 11 and their parents’ level of education. Twenty-five per cent of children whose parents had no educational qualifications were obese and a further 14 per cent were overweight.

By contrast, 15 per cent of children who had at least one parent with a degree were obese and the same proportion was overweight. No link was found between children’s weight and their parents’ social class.
Overweight and obesity at age 11 were, however, strongly associated with the mother’s weight. Children with obese mothers were most likely to be overweight (19%) or obese (36%) themselves.

Children’s weight has been measured in MCS surveys at ages 3, 5, 7 and 11. Overall, almost half (49%) of the millennium children were classified as overweight or obese in at least one of the four surveys.

Those who were obese at age 11 were less likely than other children to be ‘completely happy’ with the way they looked, the researchers found. They were also slightly more likely to say they were ‘not happy at all’ with their appearance.

For girls, there was a link between weight and how they felt about life as a whole. Girls who were not overweight were more likely to report being ‘completely happy’ than those who were classified as obese. No association was found for boys.

“These findings highlight the value of the Millennium Cohort Study for addressing issues relating to child health and, in particular, for advancing our understanding of the ‘obesity epidemic’,” Dr Connelly said. “One of the key issues we now need to focus on is why there was such a sharp increase in overweight and obesity among the MCS children between ages 7 and 11.”

Read the briefing paper

Child overweight and obesity: Initial findings from the Millennium Cohort Study Age 11 survey (PDF)

Podcast: Children’s physical development – with Roxanne Connelly

Further information

David Budge
020 7911 5349
07881 415362

Meghan Rainsberry
020 7612 6530

Notes for editors

Millennium Cohort Study: weight status by gender and country at age 11

Not overweight
Gender Male 63.6 15.4 21.1 100
Female 66.3 14.9 18.8 100
Country England 65.2 15.2 19.7 100
Wales 59.7 17.2 23.2 100
Scotland 66.9 14.1 19.0 100
Northern Ireland 60.1 15.8 24.1 100
  1. The Millennium Cohort Study is following children born in the UK between September 2000 and January 2002. The study is managed by the Centre for Longitudinal Studies at the Institute of Education, London. The five surveys of cohort members conducted so far – at ages 9 months and 3, 5, 7 and 11 years – have built up a uniquely detailed portrait of the children of the new century. The study has collected information on diverse aspects of their lives, including behaviour, cognitive development, health, schooling, housing and parents’ employment and education.
  2. The Millennium Cohort Study’s survey of 11-year-olds was carried out by Ipsos MORI between January 2012 and February 2013. Trained fieldworkers conducted 13,287 interviews with the children and their parents/guardians. Data from this survey and previous MCS surveys can be downloaded from the UK Data Service.
  3. Body Mass Index (BMI) scores were used to assign children to different weight status classifications. BMI measures the ratio between height and weight. It is calculated by dividing weight in kilograms by squared height in metres (kg/m2). In children, the relationship between BMI and overweight changes over time, so the British 1990 growth reference (UK90) is used to define overweight and obesity in relation to their age and sex. Children’s BMI is classified as overweight (including obese) when it is in the top 15 per cent of the UK90 growth reference, and as obese when it is in the top 5 per cent.
  4. The study is funded by the Economic and Social Research Council and a consortium of government departments, co-ordinated by the Office for National Statistics and including the Department for Education, the Department for Work and Pensions, the Department of Health, the Department for Transport, the Home Office, the Welsh Government, the Scottish Government and the Northern Ireland Executive.
  5. The Institute of Education is a world-leading university specialising in education and the social sciences. Founded in 1902, the Institute currently has more than 7,000 students and 800 staff. In the 2014 QS World University Rankings, the Institute was ranked number one for education worldwide. It has been shortlisted in the ‘University of the Year’ category of the 2014 Times Higher Education (THE) awards. In January 2014, the Institute was recognised by Ofsted for its ‘outstanding’ initial teacher training across primary, secondary and further education. In the most recent Research Assessment Exercise two-thirds of the publications that the IOE submitted were judged to be internationally significant and over a third were judged to be ‘world leading’. On 2 December 2014, the Institute will become a single-faculty school of UCL, called the UCL Institute of Education.
  6. The Economic and Social Research Council (ESRC) is the UK’s largest funder of research on the social and economic questions facing us today. It supports the development and training of the UK’s future social scientists and also funds major studies that provide the infrastructure for research. ESRC-funded research informs policymakers and practitioners and helps make businesses, voluntary bodies and other organisations more effective. The ESRC also works collaboratively with six other UK research councils and Innovate UK to fund cross-disciplinary research and innovation addressing major societal challenges. The ESRC is an independent organisation, established by Royal Charter in 1965, and funded mainly by the Government. In 2015 it will celebrate its 50th anniversary.

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