About three in every 100,000 children under 13 in the UK and Ireland has some sort of eating disorder, according to the study published in the British Journal of Psychiatry.
Experts from University College London’s Institute of Child Health have, for the first time, carried out extensive research into the prevalence of eating disorders among those aged five to 13.
Using more than 3,000 contacts, including hospital, university and community consultant paediatricians and psychiatrists, the team was able to build up a picture of disordered eating in the very young.
Over a 14-month period, 208 cases of “early-onset” eating disorders were confirmed, with 82 per cent affecting girls and 18 per centaffecting boys.
Some 37 per cent of the young children were suffering from anorexia, around one per cent had bulimia or were over-eaters (although this is thought to be an underestimate) and 43 per cent had some other sort of eating disorder.
The remaining 19 per cent had symptoms of disordered eating, such as avoiding food, but were not preoccupied with their weight or shape.
Overall, 96 per cent of children avoided food while 84 per cent were said to have a “morbid preoccupation with food”.
Some 71 per cent feared gaining weight, 67 per cent were preoccupied with their weight, 51 per cent with their body shape and 43 per cent with excessive exercising.
Some children used laxatives, made themselves sick or were binge-eaters, the study found.
Lead researcher Dr Dasha Nicholls, a consultant child and adolescent psychiatrist, said: “Our study gives the first estimate of the incidence of early-onset eating disorders in UK and Irish children.
“It is too early to say if there has been a rise in the numbers of children with eating disorders in recent years, but we hope our research can be used as a baseline from which to monitor future trends.
“Unfortunately, many eating disorder services are aimed specifically at adolescents.
“Childhood eating disorders are not quick or easy to treat.
“For a minority of children it may be the start of a severe and enduring illness, with death rates comparable to some forms of leukaemia.
“Our study shows there is an urgent need to consider the needs of children with eating disorders separately – and not simply lower the age range of existing adolescent services.”
The likelihood of having an eating disorder increased with age; there were no cases among five-year-olds, according to the study.
The overall incidence at ages six to eight was 0.21 per 100,000, rising to 0.92 at ages eight to nine.
Aged nine to 10, incidence was 1.64, 3.56 at ages 10 to 11 and 4.46 at ages 11 to 12.
Among children aged 12 to 13, the incidence was 9.51 per 100,000 youngsters.
The study found that 50 per cent of children needed to be admitted to hospital. One year into the study, 73 per cent had improved, six per cent were worse and 10 per cent were unchanged.
At that point, almost two-thirds of the children were still receiving treatment, with seven youngsters in hospital for most of the year.
One in five (20 per cent) of the children had a history of early feeding problems, such as fussy or faddy eating.
Some 44 per cent of the children had a close family member with a history of mental illness, most commonly anxiety or depression.
The researchers said recognition of eating disorders in children by GPs could be poor so relying on a GP database to count the numbers affected was problematic.
A 1999 Office for National Statistics study reported a prevalence of 0.3 per cent for eating disorders in children aged 11 to 15.
Previous estimates from GP registries for anorexia have been 0.3 per 100,000 in children aged nine and under, and 17.5 in those aged 10 to 19.