Dr Sonia Saxena is investigating the link between childhood obesity and related medical issues.

Obesity on the rise

From 2000-2009 hospital admission rates in those aged 5 to 19 for total obesity-related diagnoses increased more than fourfold. 

The most common reasons for admission where obesity was a comorbid condition were sleep apnoea, asthma and complications of pregnancy.

Where obesity was mentioned as a comorbidity

The median age of admission to hospital over the study period was 14.0 years. 5,566 (26.7%) admissions for obesity. 15,319 (73.3%) mentioned obesity as a comorbidity. 56.2% Girls 43.8% Boys

Obesity surgery

The number of bariatric surgery procedures per year rose from 1 in 2000 to 31 in 2009 – the majority were performed on obese girls (75.6%) aged 13 to 19.

Words: Victoria James

Jones Nielsen JD, Laverty AA, Millett C, Mainous III AG, Majeed A, Saxena S (2013) Rising Obesity-Related Hospital Admissions among Children and Young People in England: National Time Trends Study. PLoS ONE 8(6)

The statistics are startling. One in ten British children starting primary school are overweight or obese – and by the time they leave in Year Six, that’s doubled to one in five. But equally startling is the fact that parents just don’t see it. When notified, more than three-quarters of parents did not recognise their child’s weight status.

These worrying facts underpin the work of Imperial’s Dr Sonia Saxena, Reader in Primary Care, whose research is shaping government policy on the ever-worsening rates of child obesity in the UK. Saxena’s inspiration comes not only from data, but also from the children and parents who attend her general practice surgery in Putney. And from frustration at the way these children are currently being served by the NHS.

“GPs are prescribing them anti-obesity drugs, on repeat prescription, which goes against what NICE guidelines say we should do,” she explains. “Bariatric surgery is being performed on children as young as 13. It’s a desperate situation.”

Saxena’s detailed research established the link between observed rates of obesity in children and the explosion in medical problems now being experienced on the NHS frontline: a 30-fold increase in bariatric surgery, a fourfold increase in hospital admissions for obesity-linked conditions such as asthma and sleep apnea, a surge in prescribing for high cholesterol and high blood pressure, and rocketing rates of diabetes.

To unearth these deeply concerning trends, Saxena analysed a decade’s-worth of ‘hospital episodes’ data from 2000 institutions, when there was either a primary (directly causal) or secondary diagnosis of obesity in an admitted child. And her GP experience reveals the human stories behind the statistics.

“Children are coming in depressed, for instance, or needing knee replacements,” she says. “There is a very large rise in teenage girls admitted to hospital during pregnancy. Obviously there are social challenges related to pregnancy at that age, but from a biological point of view, up to age 25 is pretty much the best time to have a baby. Yet we’re seeing life-threatening complications in mother and child due to obesity.”

A second strand of her work relates to the disproportionate incidence of obesity in certain ethnic groups. “It’s the ‘thrifty gene’ theory,” she explains. “When you take people with efficient Asian genes and put them into an environment of abundance, their bodies store fat efficiently – but too efficiently.”

It’s a phenomenon that Kolkata-born Saxena has seen, she notes sadly, among her own family members. But she has tracked it extensively in Britain’s child population, finding that girls of Pakistani origin and Afro-Caribbean boys are disproportionately overweight.

This in turn creates hotspots of childhood obesity in areas with large ethnic populations. Her groundbreaking research identified locations “such as Birmingham and parts of London where, by age 11, nearly two-thirds of children are overweight or obese.”

Having documented the scale of the problem in the UK, Saxena now aims to achieve the best solutions. And as with everything in this controversial field – there was uproar in mid-August, for example, when ambitious targets that many campaigners fought for were omitted from the government’s draft childhood obesity plan – data is driving her forward.

She is focusing on that phenomenon of parental blindness to their child’s weight. The goal is twofold: how to ensure parents recognise that their child’s weight is problematic, and how then to help both child and family tackle it.

The National Childhood Measurement Programme weighs and measures all children when they enter and leave primary school. This is how we know that overweight or obese measurements double from one in ten children to one in five during those years. Parents are informed by letter of their child’s status: underweight, normal, overweight or obese. And here is where things get both worrying, and interesting.

Eighty per cent of parents who were told their child was overweight hadn't known it was the case"


“We followed up on 18,000 of those letters,” Saxena explains. “Eighty per cent of parents who were told their child was overweight hadn’t known that was the case. Perception is really important here.”

So what did the parents do next? “More than half put the letter straight in the bin. The majority took no action, often pointing to the fact that their child wasn’t as bad as others in the playground. We’re seeing a normalisation of obesity perception.”

Some parents, though, took action. One in twenty went to their GP surgeries. What happened there also shocked Saxena. “Often they were told it was just puppy fat. Their child would grow out of it.”

Here, then, are several openings for intervention. Improving parental recognition of their child’s weight status. Increasing the number of families who go to a GP after receiving such a notification. And medical practitioners offering a more robust response once families are there.

Saxena and her collaborators on a £2m grant-funded project are now focusing on those openings. They have designed an online tool to improve parental understanding and get them seeking intervention. And the best interventions, she believes, are ten-week programmes of 90 minutes after school, which provide physical activity for the child, and dietary and psychological support for the whole family.

She’s also launching a new project with Westminster Council that aims to provide evidence that this joined-up approach can work. “British children are on a trajectory that’s going up. We’ve got to get it going down,” says Saxena. The dataset shows just how urgent the task is.