Off the scales: time to act on childhood obesity

By 2050, it is said that obesity could cost the NHS almost £10 billion a year, with the full economic cost rising from around £27 billion today to £50 billion by then. Today, the Centre for Social Justice (CSJ) publishes its report, Off the scales: time to act on childhood obesity. It calls on the Government to put prevention, health, inequality and cross-departmental collaboration at the heart of its efforts to tackle childhood obesity, drawing particular attention to the need to address the question of why poorer children are at ever greater risk of being obese. It’s a question researchers at the ESRC International Centre for Lifecourse Studies at UCL, including our editor Yvonne Kelly, have been among the first to address.

There have been numerous major studies on childhood obesity over the past 10 years, many of which have shown the links with poverty. But our research looks specifically at why children from disadvantaged families are significantly more likely to be obese than their better off peers.

To examine this as robustly and rigorously as we could, we used data from the Millennium Cohort Study (MCS) which has tracked the lives of nearly 20,000 children from across the UK since the turn of the century. Using a range of measurements taken when the children were aged 5 and 11 together with detailed information about their backgrounds and family circumstances, we were able to demonstrate just how key poverty was in respect of their obesity.

At age 5, poor children were almost twice as likely to be obese compared with their better off peers. By the age of 11, the gap had nearly tripled.

Knowing as we do that obese children are less likely than their peers to grow into economically successful adults and that obesity is clearly linked with a range of chronic diseases, it’s reasonable to say that for these children, the future is far from bright. From a policy perspective it is also clear that unless the gap between rich and poor children can be closed the chances of reducing the overall obesity trend, as the Government states it is committed to doing, are pretty slim.

How is poverty linked to obesity?

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

To examine this question of whether a parent’s own lifestyle might have a role, 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 a mother was herself overweight or obese and assess children’s physical behaviour, such as how often they exercised, played and how many hours they spent watching TV or playing on a computer, and the time that they went to bed. We looked at whether the child skipped breakfast, how much fruit they ate and how often they had sweet drinks.

A lot of these factors were relevant. A mother’s behaviour when her child was very young was certainly important. Markers of an ‘unhealthy’ lifestyle here could mean as much as a 20 per cent additional risk of obesity for a child.

Obese and overweight children living in poor families were more likely to have mothers who did not breastfeed or breastfed for a shorter duration, who introduced solid foods early in infancy, who smoked during pregnancy, and who were overweight or obese. The poorest children were also more likely to spend more time watching TV and using a PC (and so have greater exposure to food and drink advertising), experience later and more irregular bedtimes, do less sports and be more physically inactive, engage less in active play with their parent, live in an area without a playground, and not have breakfast every day.

5-year-olds from poorer families were also much more likely to gain excess weight up to age 11 than richer children, leading us to conclude that the earlier certain risk factors can be challenged and the appropriate support provided for the least well off families, the greater the chance of positive impact on the risk of obesity and in a reduction in inequality.

Pathways to obesity

More recently we have identified four BMI trajectories for children. The good news is that 80 per cent of them are on a stable path where, on average, from when they’re born through to age 11, they are not overweight.

There is a small group of children who are obese at age 3 but then join the stable group by age 7. We call them the ‘decreasing’ group. There is a ‘moderate increasing group’ (13.1 per cent) where children are not overweight at age 3 but whose BMIs increase throughout childhood into the overweight (but not obese) range. Finally we have a ‘high increasing’ group of children (2.5 per cent) who are obese at age 3 and whose BMI continues to increase.

From an inequality perspective, what’s most striking here is that the wealthiest children are least likely to be in the ‘moderate increasing’ BMI group whilst the poorest children are more than twice as likely to be on the high increasing path.

Today’s CSJ report agrees with our analysis that early intervention is key and, in line with it, proposes three key early years intervention opportunities to ensure children get the healthiest start possible before they reach primary school age.

The report acknowledges that the Government is already trying to persuade families to eat more healthily and take more exercise. But it has joined a body of voices critical of the Childhood Obesity Plan, which, it believes, “fails to put reducing inequality as a goal … despite acknowledging that the childhood obesity burden falls hardest on the poorest children.”

Certainly our body of evidence indicates that policy makers need to acknowledge and address inequality as a root cause of obesity. Doing something about the structural factors in people’s lives is what is needed rather than ‘tinkering around the edges’ of the problem.

Today the CSJ asks why there are disproportionately high levels of obesity, particularly childhood obesity, in our most deprived communities. Our research has gone some way to answering that question, and makes it clear that there is no simple one-stop shop solution.

Obesity is caused by a combination of environmental, biological, cultural and psychological factors, where one factor does not dominate and yet our obsessional search for the ‘one thing’ that can tackle obesity continues. If the Government is going to reduce obesity rates, it will indeed, need to introduce multiple bold measures in tandem across the entire ecosystem and recognise that success may only be measurable after a few years.

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

BMI Development and Early Adolescent Psychosocial Well-Being: UK Millennium Cohort Study is research by Yvonne Kelly, Praveetha Patalay, Scott Montgomery and Amanda Sacker and is published in Pediatrics