Questions on 'Intervention effects of a kindergarten-based health promotion programme on obesity related behavioural outcomes and BMI percentiles'

Abstract

Kobel et al. (2019) report results of a cluster randomized trial examining the effectiveness of the “Join the Healthy Boat” kindergarten intervention on BMI percentile, physical activity, and several exploratory outcomes. The authors pre-registered their study (Steinacker et al., 2016) and described the outcomes and analysis plan in detail previously (Kobel et al., 2017), which are to be commended. However, we noted four issues that some of us recently outlined in a paper on childhood obesity interventions: 1) ignoring clustering in studies that randomize groups of children, 2) changing the outcomes, 3) emphasizing results that were statistically significant from a host of analyses, and 4) using self-reported outcomes that are part of the intervention (Brown et al., 2019).