There are a host of reasons, many of them highly publicised in recent years, as to why we should encourage young people to be more physically active. Now a team of London researchers has shown how the time spent travelling to and from school is important in helping children, particularly those from more disadvantaged backgrounds, to lower their BMI and get healthier. Anthony Laverty from Imperial College London and colleagues have been looking at the long term benefits of getting kids out of their parents’ car and onto public transport, a bike or their own two feet to get to and from school. Anthony explains how the findings could provide a fillip to efforts to tackle the childhood obesity epidemic.
In 2019, the National Child Measurement Programme showed that more than a fifth of reception-age children and more than a third of Year 6 school children were overweight or obese. Evidence from the UK and elsewhere has also shown that children who are physically inactive are likely to continue to be so as they grow up. It’s a problem the Government says it is committed to tackling and has promised not only to halve childhood obesity in the next 10 years but also, importantly to reduce the gap in obesity between children from the least and most privileged backgrounds.
Our research focuses on children as they move from primary to secondary school, a period characterised by big changes in their lives, including a growing independence from parents, forming new important friendships and relationships and all the external and internal physical changes associated with becoming a teenager. Research has shown that this can also be a crucial time for a young person’s health, particularly when it comes to the choices they make around eating and exercise.
So we wanted to know if ditching the car-ride to school with mum or dad in favour of walking or cycling to school at this age would have a role in reducing a child’s BMI and, if so, whether those reductions were the same or different for children from less well-off and better-off backgrounds.
Millennium Cohort Study
Our data came from the Millennium Cohort Study, which has tracked the lives of around 20,000 children born in the very early 2000s. So we were able to follow the same children up from when they were aged around 7 and then when they were 11 and finally when they were 14.
What’s great about this data is that it asks a host of questions about the circumstances the children are growing up in. This gives us a much more nuanced picture of these children than simply looking at their age and weight can tell us. In addition we could see not just the child’s weight but also their Body Mass Index (BMI) generally thought to be a better measure when looking at obesity and also their percentage body fat. We focused on how changing mode of travel to school related to changes in these health outcomes over time.
Parents and caregivers were asked how their child at around the age of 14 travelled to school and from that we created three categories:
- Car/taxi 26 percent
- Public transport 35 percent
- Cycling/walking 39 percent
From the children’s background we took into account a range of factors that might influence the relationship between active travel and obesity. These included their sex, where they lived, ethnicity, how much fruit they ate, whether they ate breakfast, screen use, how often they exercised in a week and whether they had experienced a growth spurt in recent months.
Children from less advantaged backgrounds were more likely to cycle or walk than their better off peers, with the least advantaged being the most likely to travel to school actively.
It was interesting to see that how children travelled to school changed quite a lot across the time period we looked at. More than a third of children changed their mode of transport twice and just over half changed once. This was most common between 11 and 14 – when children change from primary to secondary schooling, which is in line with what we would expect with most children moving school.
The body fat of children who switched from travelling by private car to walking or cycling was lower than those staying in the car on average by 0.6 percent. If they swapped to public transport the reduction was 0.4 percent. The biggest drops in BMI and body fat percentage were found in children from the most deprived backgrounds, with the lowest household incomes and where parents were not in work. For example, reductions in body fat were almost twice as large for children whose parents were not in work were almost twice as big as those with parents in managerial jobs.
Although other things such as eating breakfast every day and exercising regularly helped reduce body fat and BMI more, leaving the car behind and walking, cycling or even catching public transport also played a role. The research suggests that even after taking these into account, active travel may be more beneficial for children from more disadvantaged backgrounds than their more advantaged counterparts. As we know these disadvantaged children are at greater risk of being overweight or obese and the knock on effects of that later on in life, it strengthens the case for measures to make active travel easier and more accessible to everyone.
Although our research does not focus on the current pandemic, it’s worth noting that school closures and measures imposed across recent months to stop the spread of COVID19 will likely have led to reduced opportunities for children to get the physical exercise they need. With a vaccine being rolled out and some prospect of the virus being under control some time in 2021, we can only hope this situation improves dramatically.
When schools can once again operate as normal, we hope the Government’s eyes can refocus on the obesity epidemic. Our research, we think, provides some helpful information for policymakers, practitioners and parents. Safe cycle routes, school level policies that discourage driving will be worthwhile investments. With reduced air pollution and greenhouse gases from fewer cars on the road at school start and finish times, there will be knock-on benefits for us all.
The simple message seems to be that, where we can let’s break the cycle by getting on it or at least by not using the car! Let’s break the cycle by getting on it!
Associations of active travel with adiposity among children and socio-economic differentials: a longitudinal study is research by Anthony Laverty, Thomas Hone, Anna Goodman, Yvonne Kelly and Christopher Millett.