Effectiveness and cost-effectiveness of The Daily Mile on childhood weight outcomes and wellbeing: a cluster randomised controlled trial

Abstract

Background The Daily Mile is designed to increase physical activity levels with children running or walking around school grounds for 15-min daily. It has been adopted by schools worldwide and endorsed as a solution to tackle obesity, despite no robust evidence of its benefits. We conducted a cluster randomised controlled trial to determine its clinical and costeffectiveness. Methods Forty schools were randomly assigned (1:1) to either the Daily Mile intervention or control group in which only the usual school health and wellbeing activities were implemented. The primary outcome was BMI z-score (BMIz) at 12 months follow-up from baseline, with planned subgroup analysis to examine differential effects. Primary economic analysis outcome was incremental cost per Quality-Adjusted-Life-Year (QALY) gained. Results Using a constrained randomisation approach, balanced on school size, baseline BMIz and proportion of pupils eligible for free school meals, 20 schools were allocated to intervention (n = 1,153 participants) and 20 to control (n = 1,127); 3 schools withdrew (2 intervention, 1 control). At 12 months, BMIz data were available for 18 intervention schools (n = 850) and 19 control schools (n = 820 participants). Using intention-to-treat analysis the adjusted mean difference (MD) in BMIz (intervention − control) was −0.036 (95% CI: −0.085 to 0.013, p = 0.146). Pre-specified subgroup analysis showed a significant interaction with sex (p = 0.001) suggesting a moderate size benefit of The Daily Mile in girls (MD −0.097, 95% CI −0.156 to −0.037). This was consistent with the exploratory economic results that showed The Daily Mile to be highly cost-effective in girls (£2,492 per QALY), but not in boys, and overall to have a 76% chance of costeffectiveness for the whole sample, at the commonly applied UK threshold of £20,000 per QALY. Conclusions Overall the Daily Mile had a small but non-significant effect on BMIz, however, it had a greater effect in girls suggesting that it might be considered as a cost-effective component of a system-wide approach to childhood obesity prevention.

“…The Way That You Do It”: An Exploratory Study Investigating a Process- versus Outcome-Oriented Approach to School-Based Physical Activity Promotion

“…That is, participants in TDM schools demonstrated a significant decrease in PA levels from baseline to follow up (8 months later), while participants at ASF schools experienced an opposing trajectory and demonstrated a significant increase in PA levels over the same timeframe. Results relating to participants at TDM schools present as being in line with those of Breheny et al (2020) who suggest that The Daily Mile initiative is beneficial in the immediate (i.e. within the first 4 -6 months) but does not sustain interest (from either the teachers and/or children) over time.…”

Sociodemographic profiles, educational attainment and physical activity associated with The Daily Mile™ registration in primary schools in England: a national cross-sectional linkage study

“…It appears to be a wide-reaching intervention reaching high-performing and low-performing primary schools alike and local authority areas with better and poorer health. If it can be assumed that the physical fitness benefits of TDM seen in small trials to date are sustainable, 14 15 17 then our findings that it is taken up by urban schools serving disadvantaged school populations suggest added value from TDM over other interventions, that when scaled have failed to reach populations of children most in need. 39…”

“…12 13 A growing evidence base suggests that TDM increases physical activity and fitness over the first 12 months of its adoption, 14 15 but evidence of its impact on educational performance, well-being or maintaining healthy weight is limited. 16 17…”

Activity patterns of primary school children during participation in The Daily Mile

“…Moreover, current evidence on the chronic effects of The Daily Mile on children’s cardiorespiratory fitness is contradictory. While some studies found improvements to cardiorespiratory fitness at 12 weeks 54 – 56 , others reported no effects to cardiorespiratory fitness following six 57 or 12 months of participation 58 . Future research could thus consider whether making adaptations to The Daily Mile and/or implementing a different activity may be more successful in contributing to these targets and improving cardiorespiratory fitness in both sexes.…”