Weight reduction and dietary improvements in a cluster-randomised controlled trial for adults with intellectual disabilities

Background: People with intellectual disabilities (IDs) have an increased risk of obesity and health concerns related to their nutritional status and dietary intake. Objective: To assess the effectiveness of a multi-component intervention on weight, waist circumference (WC), clinical health parameters and dietary habits in a group of overweight and obese adults with mild-to-moderate ID. Design: A 7-month cluster-randomised trial and a 7-month follow-up of the intervention group after the end of intervention when the group received usual care. The intervention consisted of monthly dietary-group courses tailored to the participants' cognitive abilities and practical skills, monthly nutritional courses for staff, use of behaviour change techniques and nudging. The control group received usual care during the intervention. Results: There were 32 participants aged 22-61 years: 15 in the intervention group and 17 in the control group. After 7 months, a non-significant weight difference (median difference = -1.25 kg; 95% confidence interval [CI] = -2.00; 0.95 vs. +1.00 kg; CI = -1.15; 3.00, P = 0.08) and a significant WC difference were observed between the intervention and control groups (median difference = -3.75 cm; CI: -7.68; 0.11 vs. 0 cm; CI = -3.99; 1.00, P = 0.03), respectively. The median reduction in WC continued in the intervention group during the 7-month follow-up (median difference = -7.50 cm; CI: -13.57; -3.16, P = 0.002). A significant difference in frequency intake of fruit (P = 0.03) and berries (P = 0.004) was observed between the groups after 7 months, supported by a significant increase in measured serum-carotenoid levels in the intervention group after 7 months (median difference = 0.26 mmol/L; CI: -0.12; 0.52, P = 0.007). Conclusions: A significant difference in WC was observed between the groups, accompanied by changes in blood parameters and dietary habits.