Long-term follow-up of the impact of brief sleep and lifestyle interventions in infancy on BMI z-score at 11 years of age: The POI randomized controlled trial.

Objective: To determine whether BMI differences observed at 5 years of age, from early intervention in infancy, remained apparent at 11 years.

Methods: Participants (n = 734) from the original randomized controlled trial (n = 802) underwent measures of body mass index (BMI), body composition (DXA), sleep and physical activity (24-h accelerometry, questionnaire), diet (repeated 24-h recalls), screen time (daily diaries), wellbeing (CHU-9D, WHO-5), and family functioning (McMaster FAD) around their 11th birthday. Following multiple imputation, regression models explored the effects of two interventions ('Sleep' vs. 'Food, Activity and Breastfeeding' [FAB]) using a 2 × 2 factorial design.

Results: Five hundred twelve children (48% female, mean [SD] age 11.1 [0.1] years) returned for the 11-year assessment (63% of original sample). Significant differences in BMI z-score (mean difference; 95% CI: -0.16; -0.41, 0.08) or the risk of overweight (including obesity) (odds ratio; 95% CI: 0.85; 0.56, 1.29) were no longer observed between children who had received the sleep intervention compared with those who had not. By contrast, children who had received the FAB intervention had greater BMI z-scores (0.24; 0.01, 0.47) and a higher risk of obesity (1.56; 1.03, 2.36) than children not enrolled in FAB. No significant differences were observed in any lifestyle variables nor wellbeing measures across all groups.

Conclusions: Sustained reductions in BMI and obesity risk from an early sleep intervention were not apparent 9 years later, whereas a more traditional lifestyle intervention resulted in increased rates of obesity, not explained by any differences in lifestyle behaviours measured.

Clinical trial registry: ClinicalTrials.gov number NCT00892983, https://clinicaltrials.gov/study/NCT00892983.