Nearly one in five children in the UK live in constant poverty, research suggests.
A study found 19 per cent of youngsters grow up in households with an income that is 60 per cent less than the national average.
Children who experience poverty throughout their youth are three times more likely to develop mental-health problems, the research adds.
They are also twice as at risk of suffering from a lingering illness and one-and-half times more likely to be obese.
The study was carried out by the University of Liverpool and led by Dr Eric Lai, a postdoctoral research fellow in the department of public health and policy.
Poverty affected 30 per cent of children in the UK between 2016 and 2017 – a 27 per cent rise from 2010-to-2011, the researchers wrote in the journal BMJ.
And these numbers are expected to continue to increase over the next five years.
Growing up in poor surroundings has been shown to affect a child’s cognitive, social and behavioural development.
It has also been linked to low self-esteem among both youngsters and their mothers.
These poor health outcomes can continue into later life, with education and employment also being affected, the researchers wrote.
However, few studies have looked at how growing up in and out of poverty affects a youngster’s health.
The researchers therefore analysed data on 10,652 children from the UK Millennium Cohort Study, which follows 19,000 people who were born between 2000 and 2002.
Poverty, defined as having a household income of less than 60 per cent of the average, was measured when the children were nine months old, and again at three, five, seven, 11 and 14 years.
The youngsters’ physical health was determined by looking at their BMI.
And their mental wellbeing was assessed via a questionnaire that asked about any hyperactivity, emotional problems or issues with peers.
The children’s parents also reported any lingering illnesses the youngsters had at 14.
Results revealed that while 19.4 per cent of the participants were living in poverty at every check-up in the experiment, 62.4 per cent were not.
Some 13.4 per cent experienced poverty during their early childhood (between nine months and seven years old) and five per cent did from 11-to-14.
After adjusting for the mothers’ education and ethnicity, the researchers found experiencing poverty for any length of time worsens a teenager’s physical and mental health.
Experiencing poverty in early life was linked with a greater risk of obesity in a person’s teenager years than in their late childhood.
In contrast, poverty during late childhood was more strongly associated with reduced mental wellbeing and lingering illnesses.
The researchers warn poverty’s effect on a child’s mental health ‘is likely to have profound implications for social policies and their associated social costs, given mental health tracks from early life to adulthood’.
They are therefore calling for a ‘renewed commitment’ from the Government to prioritise ending child poverty.
Health professionals in particular ‘are well-placed to argue policies and services in the UK should fulfill our moral and legal responsibility to ensure every child is able to achieve their full potential’, they wrote.
The researchers stress, however, this was an observational study, with no evidence of cause-and-effect.
Many of the measures also relied on the participants self-reporting their circumstances, which can lead to inaccuracies and missing data.
Nonetheless, the study was large, nationwide and consistent with the findings of past investigations, the researchers add.