Changes in physical activity across a 6-month weight loss intervention in adolescents with intellectual and developmental disabilities.

Only 30 of the 110 participants had usable accelerometer data at 6 months and only 24 had it at both time points, so the main result rests on a small and possibly unrepresentative slice of the sample. The authors say this missing data must be considered when reading the results. The cut-off points used to define moderate-to-vigorous activity were developed in typically developing adolescents and adults. The authors note that people with intellectual and developmental disabilities have different gait and energy use, and no cut points have been validated for them, so the absolute minutes may not be accurate. Accelerometers were worn at the hip, which this population often refuses or forgets. The authors note that wrist-worn devices were worn more often in this trial, but their accuracy in adolescents with intellectual and developmental disabilities has not been established. Everyone had mild-to-moderate intellectual disability, was overweight or obese, lived with a parent, and was motivated to lose weight. The authors state the results do not generalize to all adolescents with intellectual and developmental disabilities. The intervention bundled diet, twice-monthly counselling, self-monitoring, and step goals together, so this study cannot show which part, if any, produced the small change in activity. Physical activity was a secondary analysis rather than the trial's main outcome, and the trial ran in a single metropolitan area.

No authors declare any conflicts of interest. The paper is indexed as receiving extramural research support from the National Institutes of Health.

Do not read the rise from 15.2 to 19.7 minutes a day as the programme working. That increase did not reach significance (p = 0.119) and it comes from just 24 people who could provide usable accelerometer data at both time points. Most participants were still far below the recommended hour a day.