Anorexia in children as young as eight has doubled in the past decade, new estimates reveal.
And the figures show that the slimming mental health disorder could begin earlier than previous research has suggested.
The annual number of new cases of eight to 12 year olds hospitalised or in special clinics rose from approximately 1.5/100,000 to 3.2/100,000 between 2006 and 2015.
Researchers say while the incidence rates for younger children are likely to have increased, this estimate was also based on GP records so may be more accurate than previous estimates.
The data was drawn from monthly records, submitted by specialist psychiatrists to the Child and Adolescent Psychiatry Surveillance System in the UK and Ireland for a period of eight months in 2015.
The figure for eight to 12 year olds in 2006 rose to 2.1/100,000 when other eating disorders that may now be diagnosed as anorexia were included.
The study looked at eight to 17-year-olds, and found 305 new cases were diagnosed.
Based on these figures, the researchers calculated an annual incidence rate of 26/100,000 for girls and 2/100,000 for boys, with an overall rate of 14 new cases for every 100,000 children and teens aged eight to 17.
Most of those new cases were in young women (91%) from England (70%) and of white ethnicity (92%).
The rate of new cases rose steadily with age, but substantially dropped by half at the age of 17.
For girls, the peak age was 15, and for boys it was 16.
Calculations indicated a rate of 4/100,000 for 11-year-olds, and 12/100,000 for 12-year-olds.
Principal investigator Sarah Byford, a professor in health economics at King’s College, London, said this is part of a larger study on the cost effectiveness of treating eating disorders in children and adolescents.
She said: “Service providers and commissioners should consider the evidence to suggest an increase in the number of new cases in younger children
“Future research should explore the development of earlier interventions, given evidence of an increase in incidence in young children, suggesting that onset of anorexia nervosa may be starting earlier for some young people than suggested by previous research.”
She added: “The big message that needs to be put out is that it may be the case that children and adolescents are suffering more from anorexia nervosa.
“What may be the case is that we’ve simply got better at identifying it.
“The media has played a big part in allowing parents and schools to identify the signs of anorexia nervosa.
“It’s being recognised earlier and earlier. This can only be a good thing because it means that doctors can treat it as soon as possible.”
The study authors, all from universities across the UK and Ireland, said they were unable to point of causation.
Researchers encouraged service providers and commissioners to “consider the evidence to suggest an increase in the number of new cases in younger children”.
The study was published in the BMJ Open Journal.