Efforts to prevent the development of overweight/obesity have increasingly focused early in the life course as we recognise that both metabolic and behavioural patterns are often established within the first few years of life. Randomised controlled trials (RCTs) of interventions are even more powerful when, with forethought, they are synthesised into an individual participant data (IPD) prospective meta-analysis (PMA). The EPOCH Collaboration was formed in 2009 to undertake this project.
EPOCH comprises four RCTs of obesity prevention strategies commencing before 6 months of age. Its main objective was to determine if early intervention to prevent childhood obesity impacts on body mass index (BMI) z-scores at age 18-24 months. Secondary endpoints include: overweight / obesity, breastfeeding, TV viewing, sleeping patterns, physical activity, dietary quality, parenting self-efficacy and feeding practices. Data from these studies were prospectively planned to be combined into an IPD set. The principal analysis method for aggregating the data across trials was a one-step linear modelling approach that included treatment effect as a fixed effect and accommodated the clustering introduced by one trial. Multiple-imputation was used to evaluate the impact of missing data for the primary endpoint.
The study cohort of four trials comprises 2196 women/infants. Data for the primary outcome were available for 78% of the cohort. The mean BMI-z score at 18-24 months was 0.67 (95% CI: 0.60 to 0.74) for the intervention group and 0.80 (95% CI: 0.73 to 0.87) for the control group. The estimated difference was -0.13 (95% CI: -0.23 to -0.03; p=0.012). The multiple-imputation analysis estimated the difference at -0.10 (95% CI: -0.20 to 0.00; p=0.04). Median duration of breastfeeding was significantly longer in the intervention arm (35 weeks [95% CI: 30 to 37] versus 28 weeks [95% CI: 26 to 30]; HR=0.89 [95% CI:0.8 to 0.98]; p=0.022). The proportion of children viewing TV for > 1 hr/day was significantly lower in the intervention arm (24% versus 35%; OR=0.63 [95% CI: 0.49 to 0.81; p= <.001]). There were no significant differences in overweight/obesity, sleeping patterns or physical activity.
Early interventions for the prevention of childhood obesity appear effective in achieving a reduction in BMI z-scores at 18-24 months to a moderate degree, as well as prolonging breast feeding time, and reducing TV viewing time.