Objective: To determine in low birth weight infants the relations of being small for gestational age at birth, microcephalic at birth, low weight for age at 2 years, and microcephalic at 2 years to full scale intelligence quotient (FSIQ) at the age of 16 years.
Methods: A prospective observational study of 422 of 837 eligible nondisabled low birth weight (<2000 g) adolescents from the newborn brain hemorrhage cohort with weight and head circumference at birth and at the age of 2 years in whom FSIQ was assessed with the Wechsler Abbreviated Scales of Intelligence at the age of 16 years.
Results: In a multiple regression analysis, being small for gestational age (β = −0.14, p = .02) and microcephalic at 2 years (β = −0.18, p < .001), but not low weight for age at 2 years or microcephaly at birth, had significant independent effects on 16-year FSIQ. After adjusting for pre-, peri-, and postnatal risk factors for poor cognitive performance, the independent effects of being small for gestational age (β = −0.13, p = .004) and microcephalic at 2 years (β = −0.13, p = .01) persisted. In this analysis, birth social risk had the largest significant independent effect on 16-year FSIQ (β = −0.28, p < .001).
Conclusions: Being small for gestational age at birth, but not low weight for age at 2 years, and microcephaly at 2 years, but not at birth, were independently related to FSIQ of nondisabled low birth weight adolescents, both with and without control for pre-, peri-, and postnatal risk factors.
From the *Department of Pediatrics, Columbia University and Morgan Stanley Children's Hospital of New York-Presbyterian, New York, NY; †Department of Psychiatry, Columbia University and New York State Psychiatric Institute, New York, NY; ‡Department of Primary Health Care, University of Oxford, Headington, Oxford, United Kingdom; §School of Nursing and School of Medicine, University of Pennsylvania, Philadelphia, PA; ∥Departments of Epidemiology and Department of Pediatrics and Human Development, College of Human Medicine, Michigan State University, East Lansing, MI.
Received January 12, 2009; accepted September 2, 2009.
This work was supported by NIH grant R01NS20713, NIMH grant 5 R01 MH57514-05, and March of Dimes grant 12-FY03-46.
Address for reprints: John M. Lorenz, MD, Division of Neonatology, Morgan Stanley Children's Hospital of New York-Presbyterian, 3959 Broadway, CHC 115, New York, NY 10032; e-mail: email@example.com.