Understanding Obesity Risk in Intellectual and Developmental Disabilities: Key Diagnoses and Factors

Background: Individuals with intellectual and developmental disabilities (IDD) have obesity rates nearly twice those of the general population, leading to higher rates of diabetes, hypertension, sleep apnea, and reduced quality of life.1 Genetic syndromes such as Prader-Willi syndrome (PWS) and conditions like autism spectrum disorder (ASD) and Down syndrome (DS) feature distinct mechanisms driving weight gain.2 The burden of obesity in IDD exacerbates health disparities and strains caregivers and healthcare systems.3 Yet, comparative obesity prevalence and its drivers across specific IDD diagnoses remain poorly characterized.4 Hypothesis: Obesity prevalence and underlying risk factors differ among IDD diagnoses such as ASD, DS, and PWS.5 Individuals with IDD are at high risk of comorbidities such as cardiovascular disease due to the increased prevalence of obesity. Methods: Narrative review of RCTs, clinical trials, systematic reviews, and meta-analyses on obesity in IDD (2010–2025, English, U.S. studies only). Results: • ASD: Elevated obesity driven by low activity, selective eating, and medication side effects.6 • Down syndrome: High obesity linked to hypotonia, hypothyroidism, and reduced metabolism.7 • Prader-Willi syndrome: Near-universal obesity due to hyperphagia and hypothalamic dysfunction.8 • Broader IDD: Obesity correlates with increased rates of diabetes, hypertension, sleep apnea, and metabolic syndrome.9 Conclusions: Obesity risk varies markedly by IDD diagnosis. Syndrome-specific biological and behavioral mechanisms warrant tailored prevention and intervention strategies to reduce health disparities and improve long-term outcomes.10