MCH Student:

Megan Linn

Date of Defense:

May 23, 2013

Abstract:

Objective
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.

Study Design
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.

Results
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.

Conclusions
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.