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Children's growth patterns 'predict obesity risk before age 5'

Wednesday 27 March 2019

"Weighing children when they start school is already too late," reports the Mail Online.

A study on childhood obesity suggests children's weight and growth patterns should be measured before they start school.

One in 3 children in the UK are overweight or obese by the time they leave primary school, according to Public Health England.

Researchers analysed research involving 729,000 children around the world to spot patterns of growth linked to a higher risk of being overweight or obese.

They found children's early growth patterns may have an impact on their chances of becoming overweight in later life.

In UK schools, children's height and weight are measured in reception class (age 4 or 5) and year 6 (age 10 or 11).

Researchers say that collecting children's weight only twice during their school age years means opportunities to spot children at high risk of becoming obese adults could be missed.

Find out more about the child measurement programme

Where did the story come from?

The researchers who carried out the study were from the University of Manchester in the UK.

No information about funding was provided.

The research was published in the peer-reviewed journal Preventive Medicine Reports and is free to read online.

The Mail Online's main headline – that children should be weighed from age 2 – is not based on findings in the research paper, but comes from an interview with the lead researcher.

The news story does not go into detail about the complex research methods or results, but gives an overview of the study's implications, with commentary from the researchers.

What kind of research was this?

This was a review of recent evidence about childhood growth and obesity, taking in papers that include measures of children's body mass index and growth curves from around the world.

While it's useful to have a summary of this research, reviews are only as good as the studies included.

What did the research involve?

Researchers looked for papers that describe recent (since 2000) cross-sectional surveys of children's BMI, broken down by age and gender, with more than 1,000 participants.

They also looked for studies of any size that followed a group of children over time, looking at changes to their BMI between ages 4 and 11.

They created graphs showing the average BMI of girls and boys at different ages from different countries.

They then grouped them into "high charting" countries with higher BMIs and "low charting" countries with lower BMIs, with outliers for the very high charting countries.

They also summarised the results of the studies that followed groups of children over time, looking at common "developmental trajectories" or pathways, where BMI rose and fell in relation to the children's growth as they got older.

They used these to identify high-risk patterns that indicated children might be more likely to become overweight or obese in the long term.

What were the basic results?

Researchers found 46 studies looking at the BMI of different children of various ages.

These were used to estimate population level BMIs for each country.

Only 8 studies followed children's growth and weight over time, which were used to estimate growth patterns.

The researchers said they identified 2 basic childhood growth patterns that predicted an increased chance of adult obesity:

  • "early increasing" BMI growth, which included children who were overweight from infancy
  • "late increasing" BMI growth, which included children who had their mid-childhood growth spurt early, at age 2 to 3 years

Children who entered their growth spurt at 4 to 5 years were classed as being at "normal" risk of becoming overweight.

The "high charting" areas with higher average BMIs at all ages included groups from China, Japan, Iran, Cameroon and Europe (including the UK).

The "low charting" area included groups of children from India, Vietnam, some groups in China and other Asian countries.

The researchers found "extremely high" childhood BMI among groups from Pacific Island children in New Zealand, Kuwait, the US, South Korea and Pakistan.

How did the researchers interpret the results?

The researchers said their research showed that childhood growth patterns "vary within and between populations and may change over time".

But their main worry is that taking one-off measurements of different children at various ages does not capture how an individual child's BMI changes as they grow up.

It only gives average BMIs for each age group. This makes it hard to see which children are more at risk of becoming obese as adults.

They also warned that "recent data for this age group [4 to 11] is lacking from many of the world's most obese nations and is needed to assess global risk" of obesity.

Conclusion

This study is complex and includes a great deal of data from many different types of studies, in widely varying populations worldwide.

It's not easy to pick out results immediately relevant to UK children. The review included only 3 studies from the UK involving 12,105 children.

Some of the results were based on small surveys that did not include important information, such as the year or how the data was collected, or a description of how children were selected to take part.

But the study does suggest that children's early growth patterns may have an impact on their chances of becoming overweight in later life.

If we collect information on children's weight only twice while they're at school, children with growth patterns putting them at high risk of becoming overweight or obese in adulthood might be missed.

This information is mainly useful for people designing public health interventions, such as the childhood measurement programme.

It probably will not help you tell if your child is overweight, or at risk of becoming overweight.

But there are plenty of things you can do already to help your child grow at a healthy weight.

Get advice if your child is overweight

Analysis by Bazian
Edited by NHS Website

Links to the headlines

Weigh children from the age of TWO to prevent them from developing obesity, warn researchers

Mail Online, 26 March 2019

Links to the science

Robinson HA, Dam R, Hassan L, et al.

Post-2000 growth trajectories in children aged 4–11 years: A review and quantitative analysis

Preventive Medicine Reports. Published online March 12 2019