At age five, poor children were almost twice as likely to be obese compared with their better off peers. (Representational Image)
Poorer children are up to three times higher risk of obesity compared to their better-off peers, a new UK study has found.
Researchers from University College London and London School of Economics used data from the Millennium Cohort Study (MCS), which tracks nearly 20,000 families from across the UK.
The study used measurements made when the children were aged five and again at age 11.
The link between relative poverty and childhood obesity was stark. At age five, poor children were almost twice as likely to be obese compared with their better off peers.
As many as 6.6 per cent of children from families in the poorest fifth of the sample were obese while the figure for the richest fifth was just 3.5 per cent.
By the age of 11 the gap had widened, nearly tripling to 7.9 per cent of the poorest fifth were obese and for the best-off, the figure was 2.9 per cent.
The researchers examined many aspects of a child's environment and health behaviours. The environmental factors looked at were aspects 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.
They also factored in the degree to which the mother was herself overweight or obese.
"Intervening in the early years when the family environment has more profound influences on children's healthy development has the potential to be particularly effective," said Yvonne Kelly, a professor at University College London.
To assess the impact of physical behaviour, the study compared the frequency of sport or exercise, active play with a parent, hours spent watching TV or playing on a computer, journeys by bike and the time that children went to bed.
It also compared dietary habits such as whether the child skipped breakfast as well as fruit and sweet drink consumption.
"The 'structural' causes of socioeconomic inequalities have to be addressed along with tackling 'inherited' obesity via lifestyle factors that tend to go with lower incomes.
Early intervention with parents clearly has huge potential.
And evidence from our work suggests that this should start before birth or even conception," Ms Kelly said.
The study found that doing sport more than three times a week played an important role, as did an earlier bedtime and regular fruit consumption which were both positively associated with downward movement in weight categories.
However, maternal smoking during pregnancy and a mother's Body Mass Index (BMI) were negatively associated with downward movement across weight categories.
Overall, the study found that markers of 'unhealthy' lifestyle here could mean as much as a 20 per cent additional risk of obesity for a child.
The findings were published in The European Journal of Public Health.