Effects of exercise training on obesity-related parameters in people with intellectual disabilities: systematic review and meta-analysis

Background Efforts to synthesise existing knowledge concerning the effects of exercise interventions on obesity (i.e. changes in body weight and composition) have been made, but scientific evidence in this matter is still limited. This systematic review and meta-analysis aims to identify and critically analyse the best available evidence regarding the use of physical exercise as a strategy to attenuate obesity through its effects on adiposity-related anthropometric parameters in people with intellectual disability (ID). Methods Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a literature search was performed using PubMed, Scopus, SPORTDiscus, CINAHL and the Cochrane Library through specific keywords up to July 2020. The search adhered to the population, intervention, comparison and outcome strategy. Randomised controlled trials addressing the effects of the exercise intervention on adiposity-related anthropometric parameters (body mass index, waist circumference, waist-hip ratio, fat percentage or body weight) in children, adolescents and adults with ID were included. The methodological quality of the studies found was evaluated through the PEDro scale. Results A total of nine investigations with children and/or adolescents (10-19 years) and 10 investigations with adults (18-70 years) were selected, mostly experiencing mild and moderate ID. Methodological quality was fair in 13 of these publications, good in five and excellent in one. Seventeen trials reported comparable baseline and post-intervention data for the intervention and control groups and were included in the meta-analysis. In nine studies, the intervention group performed a cardiovascular training programme. Five papers described a combined training programme. Two trials executed whole-body vibration training programmes, and one publication proposed balance training as the primary intervention. According to the meta-analysis results, the reviewed studies proposed exercise modalities that, in comparison with the activities performed by the participants' in the respective control groups, did not have a greater impact on the variables assessed. Conclusions While physical exercise can contribute to adiposity-related anthropometric parameters in people with mild and moderate ID, these findings show that exercise alone is not sufficient to manage obesity in this population. Multicomponent interventions appear to be the best choice when they incorporate dietary deficit, physical activity increase and behaviour change strategies. Finding the most effective modality of physical exercise can only aid weight loss interventions. Future research would benefit from comparing the effects of different exercise modalities within the framework of a multicomponent weight management intervention.