Supplementary Material for: Association between marginally low birth weight and obesity-related outcomes indirect effects via ADHD and abnormal eating

Background: Evidence of the association between children born with marginally low birth weight (MLBW) and obesity-related outcomes was controversial, and our study aimed to examine the role of attention deficit hyperactivity disorder (ADHD) and/or abnormal eating in these associations. Methods: A retrospective cohort study consisting of 677 Chinese children was conducted. Obesity-related outcomes (BMI, waist circumference, skin fold thickness, body fat, blood pressure, lipids and blood glucose), behaviour problems (ADHD and eating behaviour) and birth weight were collected. Mediation analyses were used to explore whether ADHD and/or abnormal eating was an intermediary factor in the MLBW-OB relationship. Results: The children with MLBW tended to have higher skin fold thickness, triglycerides, fasting blood glucose, waistline, body fat and abdominal obesity risks. Birth weight was negatively related to obesity-related outcomes, and the associations were mediated, partially, by increased risk of ADHD or abnormal eating behaviour after adjustment for BMI z-score. Furthermore, lower birth weight predicted higher waist circumference indirectly through emotional overeating caused by ADHD (β: -0.10; 95% CI: -0.19, -0.01). Conclusion: Our study suggests the hypothetical role of ADHD and abnormal eating as underlying mechanisms in the association between MBLW and obesity-related outcomes, which provides novel scientific evidence for interventions of childhood development.