A dangerous eating disorder called ARFID causes nutritional deficits and malnutrition. Eating disorders impact one to five percent of the population, according to researchers.
ARFID is not about the patient’s perception of their own body or fear of gaining weight, unlike anorexia nervosa. Instead, the disorder is characterized by a sensory dislike to specific foods caused by their qualities or appearance, or by other phobias such as a fear of choking, a fear of food contamination, or a lack of appetite.
Now, Karolinska Institutet researchers have looked at the significance of genetic variables in the development of ARFID. The research included a cohort of over 17,000 sets of twins born in Sweden between 1992 and 2010. Between the ages of six and twelve, a total of 682 children with ARFID could be detected.
The twin study helped scientists assess the role of both genetics and environment in disease development.
“We know that identical twins share all genes and that fraternal twins share about half of the genes that make people different. When we then see that a certain trait is more common in both members of identical twin pairs than in fraternal twin pairs, it is an indication that there is a genetic influence. We can then estimate the degree to which a trait is influenced by genetic factors,” adds Lisa Dinkler.
The study found that a significant 79% genetic component contributed to the development of ARFID. This indicates that hereditary factors may account for 79% of the probability of getting ARFID.
“This study suggests that ARFID is highly heritable. The genetic component is higher than that of other eating disorders and on par with that of neuropsychiatric disorders such as autism and ADHD,” adds Lisa Dinkler, a postdoctoral researcher at the Department of Medical Epidemiology and Biostatistics at Karolinska Institutet.
ARFID is a rather recent diagnosis. The disorder was added to the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) in 2013 and to the ICD (International Classification of Diseases) by the WHO this year. The current version of the ICD, ICD-11, will be implemented into the Swedish healthcare system in a few years; hence, the diagnosis is not yet an official aspect of Swedish health and medical treatment.
Dr. Dinkler’s research will now examine how closely ARFID is related to other psychiatric conditions including anxiety and depression, neurodevelopmental difficulties, and digestive issues.
“We will use twin studies to test the extent to which ARFID shares underlying genetic and environmental factors with these conditions,” adds Dr. Dinkler.
Source: 10.1001/jamapsychiatry.2022.4612
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