Influence of Prenatal and Postnatal Growth on Intellectual Functioning in School-aged Children Intellectual Functioning in School-Aged Children

Pongcharoen T, Ramakrishnan U, DiGirolamo AM, et al. — Tue, 01 May 2012 00:00:00 GMT

Objective

To assess the relative influence of size at birth, infant growth, and late postnatal growth on intellectual functioning at 9 years of age.

Design

A follow-up, cross-sectional study.

Setting

Three districts in Khon Kaen province, northeast Thailand.

Participants

A total of 560 children, or 92% of former participants of a trial of iron and/or zinc supplementation during infancy.

Main Exposures

Prenatal (size at birth), early infancy (birth to 4 months), late infancy (4 months to 1 year), and late postnatal (1 to 9 years) growth. Multiple-stage least squares analyses were used to generate uncorrelated residuals of postnatal growth.

Main Outcome Measures

Intellectual functioning was measured at 9 years using the Wechsler Intelligence Scale for Children and the Raven's Colored Progressive Matrices (Pearson). Analyses included adjustment for maternal, household, and school characteristics.

Results

Significant relationships were found between growth and IQ (Wechsler Intelligence Scale for children, third edition, Thai version), but only up to 1 year of age; overall, growth was not related to the Raven's Colored Progressive Matrices. The strongest and most consistent relationships were with length (birth, early infancy, and late infancy); for weight, only early infancy gain was consistently related to IQ. Head circumference at birth was not collected routinely; head circumference at 4 months (but not head circumference growth thereafter) was related to IQ. Late postnatal growth was not associated with any outcome.

Conclusion

Physical growth in early infancy (and, to a lesser extent, physical growth in late infancy and at birth) is associated with IQ at 9 years of age. Early infancy may be a critical window for human development.

Preschool Micronutrient Supplementation Effects on Intellectual and Motor Function in School-aged Nepalese Children Intellectual and Motor Function of Nepalese Children

Murray-Kolb LE, Khatry SK, Katz J, et al. — Tue, 01 May 2012 00:00:00 GMT

Objective

To examine intellectual and motor functioning of children who received micronutrient supplementation from 12 to 35 months of age.

Design

Cohort follow-up of children 7 to 9 years of age who participated in a 2 × 2 factorial, placebo-controlled, randomized trial from October 2001 through January 2006.

Setting

Rural Nepal.

Participants

A total of 734 children 12 to 35 months of age at supplementation and 7 to 9 years of age at testing.

Interventions

Children received iron plus folic acid (12.5 mg of iron and 50 μg of folic acid); zinc (10 mg); iron plus folic acid and zinc; or placebo.

Main Outcome Measures

Intellectual, motor, and executive function.

Results

In both the unadjusted and adjusted analyses, iron plus folic acid supplementation had no effect overall or on any individual outcome measures being tested. In the unadjusted analysis, zinc supplementation had an overall effect, although none of the individual test score differences were significant. In the adjusted analysis, the overall difference was not significant.

Conclusion

In rural Nepal, we found that iron plus folic acid or zinc supplementation during the preschool years had no effect on aspects of intellectual, executive, and motor function at 7 to 9 years of age, suggesting no long-term developmental benefit of iron or zinc supplementation during 12 to 35 months of age.

JAMA Pediatrics: Global Health Theme Issue Topic Collection

Influence of Prenatal and Postnatal Growth on Intellectual Functioning in School-aged Children Intellectual Functioning in School-Aged Children

Preschool Micronutrient Supplementation Effects on Intellectual and Motor Function in School-aged Nepalese Children Intellectual and Motor Function of Nepalese Children