Date of Defense:
May 23, 2013
To determine whether birth weight, length, or body mass index (BMI), and postnatal growth rate are associated with childhood cognition and BMI in appropriate for gestational age (AGA) and large for gestational a ge (LGA) infants.
AGA (2495 – 3997 g) and LGA infants (>3997 g at ≥37 weeks,) were identified in data from the Collaborative Perinatal Project. Infants with diagnoses affecting intelligence and growth were excluded, leaving 20,611 AGA and 1054 LGA infants. The independent variables in our models were birth weight, length, BMI, and postnatal growth at 16 weeks. Linear regression modeling was used to evaluate the relationship between these measures and Wechsler Scale of Children’s Intelligence (WISC) scores and BMI at age 7 years.
LGA infants had higher 7 – year WISC scores, with full – scale scores being 2.53 points (95%CI 1.68 – 3.38) above their AGA peers. While birth weight and length are positively associated with 7 – year IQ and BMI in the AGA group, LGA infants exhibited positive associations for IQ and length but a negative association for IQ and birth BMI. Postnatal weight, length, and BMI gains were positively associated with 7 – year IQ and BMI in the AGA group. LGA infants with increasing postnatal BMI had higher BMI at 7 with small effects on IQ.
Prenatal and the first 4 months of postnatal growth are positive predictors of childhood cognitive function and of BMI. For LGA infants, further accelerated prenatal growth predicts lower IQ scores and accelerated postnatal growth predicts higher childhood BMI.