There is ongoing debate about whether eating disorders are more common in modern society. Some people say, because they are exposed to and sharing images of themselves in an unprecedented way, social media is affecting young people’s body image and may have an impact on their eating.

According to a large survey conducted in 2017, about four in every thousand people aged between five and nineteen have an eating disorder in England.

The most recent study to look at trends in eating disorders in primary care has shown more people were being diagnosed with eating disorders year on year. It found diagnoses for eating disorders increased from thirty two to thirty seven in every hundred thousand people aged between ten and forty nine between 2000 and 2009. However, the GP data used in this research dates from before the launch of social media platforms such as Instagram.

The researchers decided to look again at these trends to see if the rise of social media had changed anything. They used a large primary care database covering about 7% of the population in England, specifically looking at the anonymised records of more than one million children and young people who visited their GP between 2004 and 2014.

They found eating disorders recorded in primary care are nearly eleven times more common in females than males. They are twice as common in people aged between sixteen and twenty than in those aged between eleven to fifteen or twenty one to twenty four. They are also one and a half times as common in people from the most affluent areas compared to the least affluent areas.

The most common type of eating disorder were not the two most well known, anorexia and bulimia nervosa, but eating disorders that were “not otherwise specified”. These were eating disorders that didn’t quite reach the threshold to be defined as anorexia or bulimia nervosa.

The researchers also found fewer young people are being diagnosed with eating disorders every year in primary care. Rates decreased most significantly for bulimia nervosa, less so for eating disorders not otherwise specified, and remained stable for anorexia nervosa. Decreases were also seen in females and sixteen to twenty four year olds. Significant decreases were found in young people from the most deprived areas, whereas rates in the most affluent areas where actually higher.

The numbers of males diagnosed with an eating disorder was too small for further breakdown, with less than five hundred diagnoses over the eleven year study period. The number of both males and females with bulimia nervosa were particularly small too, although the researchers found a 50% decrease in females diagnosed.

Ann John, Clinical Professor of Public Health and Psychiatry, Swansea University and Sophie Wood, Research Assistant, CASCADE, Cardiff University, writing in The Conversation, said “It’s not easy to unpick what these findings may mean and whether social media has played a part in these changing trends. Looking at bulimia nervosa alone, some researchers suggest that bulimia nervosa is a Western phenomena, based on a pressure to be thin, while anorexia nervosa is less culture bound, and exists across time, cultures and even species.

“They say that a decrease in bulimia nervosa could be attributed to the normalisation of being overweight, which reduces the pressure to be thin and leads to a decrease in bulimia nervosa. In which case, it could be argued that social media is affecting the trend, although not in the way that some might assume. Rather than increasing eating disorders, the body positivity and range of body shapes and sizes seen on social platforms is helping young people accept their own selves. This may also explain why the decrease is more evident in more deprived areas where the prevalence of obesity is higher.

“But this concept is highly contested. And it’s hard to escape the rise in social media use and the increasing concerns about weight and body image. The mechanism where this might lead to eating concerns and disordered eating seems sensible. But our study doesn’t currently support that.

“However, we did also find an increase in the number of people receiving in-patient care for eating disorders in England, which could suggest that people are being diagnosed with eating disorders at a later, more advanced stage than previously, requiring in-patient admission. Eating disorders can be problematic conditions for doctors to identify, refer and manage for several reasons.

“Some studies have shown that diagnoses are less likely to be made if there are no specialist services in the area, for example. Greater availability of child and adolescent mental health services, and lower thresholds for acceptance of referrals than in adult services for eating disorders, could explain why eating disorder diagnosis rates for 11 to 15-year-olds have remained stable over the study period, yet decreased for 16 to 24-year-olds.

“While more research must be done to work out whether, and how, social media influences the onset and continuation of eating disorders globally, studies like ours are starting to unpick assumptions we might make about the links between the two. And ultimately will help us to focus on creating better prevention and online therapeutic tools for young people with eating disorders and those who may go on to develop them.”

The study, involving researchers from Swansea University, Cardiff University, Berkshire Healthcare NHS Foundation Trust and NCEPOD is published on BMJ Open.