The impact of hypothetical early life interventions on rapid weight gain during infancy and body mass index at 5 and 8 years in Norway: The Norwegian Mother, Father, and Child Cohort Study (<scp>MoBa</scp>)

The average population-level difference in rapid weight gain during infancy at 2 years under the intervention targeting the prenatal, early postnatal factors and these factors combined with 95% confidence intervals were -0.012 (-0.017, -0.007), -0.009 (-0.012, -0.005) and -0.020 (-0.025, -0.015), respectively. The average population-level differences in children's BMI-for-age z-score for interventions targeting early life factors, child EBRB and these factors combined were -0.225 (-0.244, -0.207), 0.02 (-0.021, 0.024) and -0.223 (-0.249, -0.196), respectively among 5-year-olds and -0.265 (-0.295, -0.236), -0.020 (-0.029, -0.011) and -0.285 (-0.315, -0.256), respectively among 8-year-olds. Our results suggested joint interventions on early life factors may reduce childhood BMI-for-age z-scores.