Co-existing mental and somatic conditions in Swedish children with the avoidant restrictive food intake disorder phenotype

Avoidant restrictive food intake disorder (ARFID) is a feeding and eating disorder, characterized by limited variety and/or quantity of food intake impacting physical health and psychosocial functioning. Children with ARFID often present with a range of psychiatric and somatic symptoms, and therefore consult various pediatric subspecialties; large-scale studies mapping comorbidities are however lacking. To characterize health care needs of people with ARFID, we systematically investigated ARFID-related mental and somatic conditions in 616 children with ARFID and >30,000 children without ARFID. In a Swedish twin cohort, we identified the ARFID phenotype in 6-12-year-old children based on parent-reports and register data. From >1,000 diagnostic ICD-codes, we specified mental and somatic conditions within/across ICD-chapters, number of distinct per-person diagnoses, and inpatient treatment days between birth and 18th birthday (90 outcomes). Hazard ratios (HR) and incidence rate ratios (IRR) were calculated. Relative risks of neurodevelopmental, gastrointestinal, endocrine/metabolic, respiratory, neurological, and allergic disorders were substantially increased in ARFID (e.g., autism HRCI95%=9.77.5-12.5, intellectual disability 10.37.6-13.9, gastroesophageal reflux disease 6.74.6-9.9, pituitary conditions 5.62.7-11.3, chronic lower respiratory diseases 4.92.4-10.1, epilepsy 5.84.1-8.2). ARFID was not associated with elevated risks of autoimmune illnesses and obsessive-compulsive disorder. Children with ARFID had a significantly higher number of distinct mental diagnoses (IRRCI95%=4.74.0-5.4) and longer duration of hospitalizations (IRRCI95%=5.51.7-17.6) compared with children without ARFID. Children with ARFID were diagnosed earlier with a mental condition than children without ARFID. No sex-specific differences emerged. This study yields the broadest and most detailed evidence of co-existing mental and somatic conditions in the largest sample of children with ARFID to date. Findings suggest a complex pattern of health needs in youth with ARFID, underscoring the critical importance of attention to the illness across all pediatric specialties. Fredrik and Ingrid Thurings Foundation, Mental Health Foundation.