Academic achievement of low birthweight children at age 11: the role of cognitive abilities at school entry.

We examine the extent to which deficits in academic achievement in low birthweight (LBW) children at age 11 are explained by deficits in cognitive abilities at school entry. Data come from a longitudinal study of a stratified sample of LBW and normal birthweight (NBW) children from an innercity and middle class suburbs in the Detroit area. Woodcock-Johnson Psychoeducational Battery-Revised was used to measure reading and math at age 11. WISC-R and specific neuropsychologic tests were administered at age 6. On reading, the LBW-NBW difference was -3.6 points (SE = 1.2). The difference was explained almost entirely by IQ at age 6. On math, the LBW-NBW difference was -6.1 points (SE = 1.1). The difference on math was trivial and not significant, when IQ and neuropsychological tests at age 6 were controlled. Level of LBW was unrelated to reading, but it had a gradient relationship with math, with birthweight < or = 1,500 g associated with a greater deficit than heavier LBW. The results imply that most of the LBW-NBW gap in academic achievement at age 11 could be eliminated by eliminating differences in cognitive abilities at age 6. Interventions to improve academic performance of LBW children should focus on the preschool years.