COPENHAGEN, Denmark — Among adolescents, body image can be a very fragile thing. A new report finds eating disorders not only impact those trying to lose weight, but can also affect children who are already skinny. Researchers say girls with a low body mass index (BMI) early on in childhood may be at a high risk of developing anorexia nervosa later on. Conversely, young girls with a high BMI are more at risk for bulimia nervosa.
“By examining the records of thousands of girls over their lifetime in national health registers, we have discovered early warning profiles that could signal girls at risk for anorexia nervosa and bulimia nervosa”, says lead author Dr. Britt Wang Jensen from Denmark’s Bispebjerg and Frederiksberg Hospital in a media release. “The difference in childhood BMI of girls who later developed eating disorders started to emerge at an early age. These results highlight the importance of regularly monitoring weight and height during childhood to identify these patterns as early as possible.”
Rates of anorexia and bulimia among adolescents, especially girls, continue to rise on a year-over-year and decade-over-decade basis. However, the exact connection between BMI years before and the onset of these conditions remains unclear. Prior research has ultimately produced conflicting results.
So, to find some answers Danish researchers analyzed data pertaining to 66,576 girls from the Copenhagen School Health Records Register (born between 1960 and 1996). Those records included information on height and weight measured during annual school health examinations between ages seven to 13. Meanwhile, researchers tracked specific bulimia and anorexia diagnoses using the Danish National Patient Register and the Danish Psychiatric Central Research Register.
When do these eating disorders begin to surface?
Over that entire time period, 514 women were diagnosed with anorexia. Researchers say the average age at the time of these diagnoses was 20 years-old. Another 315 women received a bulimia diagnosis, typically around the age of 23.
Interestingly, a closer analysis showed “inverse associations” between childhood BMI and anorexia later on. For instance, take two girls with a BMI difference of about five pounds. The somewhat heavier girl had a 50 percent higher risk of developing bulimia than the leaner child in later life. At age 13, the risk was 33 percent higher.
Additionally, in comparison to girls with a normal weight at seven years-old, overweight participants had twice the risk of developing bulimia nervosa years later.
Study authors stress that more research is needed before any conclusive statements can be made regarding bulimia, anorexia, and BMI. These findings establish associations, not concrete catalysts.
Researchers presented their findings at the European Congress on Obesity, held virtually this year.