Does food selectivity drive differences in dietary resemblance between children with intellectual disabilities and typical development?

Although children's dietary intake often resembles that of their parents', dietary resemblance has not been examined among children with intellectual disabilities (ID), where food selectivity is a common parental concern. We compared dietary resemblance in children with typical development (TD), ID, and ID and co-occurring autism (ID + A) in parent-child dyads, and examined whether child food selectivity mediated between-group differences. Dietary data from parents and their children (3-8 years, male = 61.8%, TD = 52.9%, ID = 18.6%, ID + A = 28.4%) were analyzed as mother-child (n = 100) and father-child (n = 70) dyads. Dietary resemblance was operationalized as the proportion of foods that were reported as eaten/not eaten by both parent and child in parent-completed Food Frequency Questionnaires. Food refusal rate was used to capture food selectivity (total foods children would not eat/total foods offered). Among mother-child dyads, dietary resemblance did not differ between children with ID compared to TD (P = 0.243). Among father-child dyads, dietary resemblance was 10% lower in children with ID than TD (66.4% vs. 74.1%, P = 0.032), and the difference was partially explained (mediated) by food refusal. Among mother-child dyads, dietary resemblance was 19% lower among children with ID + A than TD (61.5% vs. 75.6%, P = 0.001), and the difference was completely explained by food refusal. Among father-child dyads, dietary resemblance was 22% lower among children with ID + A than TD (57.9% vs. 74.1%, P < 0.001), and the difference was completely explained by food refusal. Subanalyses by food groups produced similar results. Compared to TD children, dietary resemblance was lower in children with ID + A, but not children with ID, and differences were explained by food selectivity. Our findings suggest parents of children with ID + A may have less influence over their child's dietary intake than parents of children with ID or TD.