Obesity in British children with and without intellectual disability: cohort study.

Background: Reducing the prevalence of and inequities in the distribution of child obesity will require developing interventions that are sensitive to the situation of 'high risk' groups of children. Children with intellectual disability appear to be one such group. We aimed to estimate the prevalence of obesity in children with and without intellectual disability in a longitudinal representative sample of British children and identify risk factors associated with obesity at age 11.

Methods: Information was collected on a nationally representative sample of over 18,000 at ages 9 months, 3, 5, 7 and 11 years. We used UK 1990 gender-specific growth reference charts and the LMS Growth programme to identify age and gender-specific overweight and obesity BMI thresholds for each child at ages 5, 7 and 11 years.

Results: Children with intellectual disabilities were significantly more likely than other children to be obese at ages five (OR = 1.32[1.03-1.68]), seven (OR = 1.39[1.05-1.83]) and eleven (OR = 1.68[1.39-2.03]). At ages five and seven increased risk of obesity among children with intellectual disabilities was only apparent among boys. Among children with intellectual disability risk of obesity at age eleven was associated with persistent maternal obesity, maternal education, child ethnicity and being bullied at age five.

Conclusions: Children with intellectual disability are a high-risk group for the development of obesity, accounting for 5-6 % of all obese children. Interventions to reduce the prevalence and inequities in the distribution of child obesity will need to take account of the specific situation of this group of children.