Heritability of the Avoidant/Restrictive Food Intake Disorder (ARFID) Phenotype in 6-to-12-Year-Old Swedish Twins

• Little is known about the etiology of avoidant/restrictive food intake disorder (ARFID) and no twin studies of ARFID exist yet. Validated screening instruments for ARFID are only starting to emerge and accordingly, few large-scale epidemiological studies specifically aimed at measuring ARFID are available. We leveraged the rich existing datasets of the Swedish Twin Registry to develop a proxy for the ARFID phenotype and determine its twin-based heritability. We extracted all data relevant to ARFID from the Child and Adolescent Twin Study in Sweden and national health registers, and identified children with avoidant/restrictive eating with clinically significant impact, but without body image concerns such as fear of weight gain and excluding major medical illnesses that could account for the eating behavior. Among 34,382 twins born 1992–2010, 678 children (2.0%, 39% female) were identified with the ARFID phenotype between age 6 and 12 years. In the best fitting model, variation in the liability to ARFID was largely explained by additive genetic factors (0.80, 95% confidence interval [CI] 0.71–0.86), with significant contributions from non-shared environmental factors (0.20, 95% CI 0.14–0.29) and sibling contrast effects (-0.11, 95% CI -0.16—-0.04). Prevalence and sex distribution of the ARFID phenotype were similar to previous studies, supporting the use of epidemiological data to identify ARFID. This first heritability estimate of ARFID suggests that ARFID is highly heritable, encouraging future twin and molecular genetic studies. In a next step we will use multivariate twinmodels to test whether, etiologically, ARFID is related to neurod-velopmental disorders.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Psykiatri (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Psychiatry (hsv//eng)

Nyckelord

Eating disorder

Genetics

Twin study

Measurement

Neurodvelopmental disorders

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