A study published in BMJ Open found cases rose by 15% between 2000 and 2009, with teenage girls most at risk. Researchers said the true numbers affected may be far higher as many do not seek medical help.
A team led by Dr Nadia Micali from the University College London examined data from the General Practice Database, containing records of 5% of the UK population.
They found 9,072 cases of eating disorders between January 2000 and December 2009 among this subset of the population.
It suggests there were around 180,000 cases across the UK in this time.
Researchers discovered that between 2000 and 2009, rates of eating disorders among 10- to 49-year-olds increased from 32.3 to 37.2 cases per 100,000 people.
Researchers found that eating disorders were most common among girls aged 15-19 years old and boys aged 10-14.
'More common than type 1 diabetes'
Anorexia nervosa accounted for 23% of cases and bulimia nervosa 38%, although both remained stable over the decade. The increase in diagnoses overall was driven by cases of ‘eating disorder not otherwise specified’, which made up 39% of all cases over this time.
The findings suggest there are 4,610 new cases of eating disorders in girls aged 15-19 each year across the UK.
Researchers said that among girls aged 10-19, there are nine times as many new cases of eating disorders as new cases of type 1 diabetes.
They said cases may be due to better detection or a real rise in cases.
Study authors said the incidence rates are based on primary care diagnoses and reflect healthcare need rather than the number of cases overall.
They said: ‘There is evidence that true rates might be double or triple those detected in a healthcare setting.’