PARENTAL FACTORS IN COGNITIVE OUTCOME OF NONHANDICAPPED LOW-BIRTH-WEIGHT INFANTS

A population based cohort of 144 children weighing less than 2000 g wh o were without major handicap, and a random control sample of 163 chil dren born at term and weighing over 3000 g were investigated. The aim was to assess the relative importance for cognitive development at 5 y ears of age, of birthweight, parental demographic factors, and factors related to the environment in which the child was reared. The mean no n-verbal IQ was 6.1 points lower (95% CI, 2.3 to 10) for the low birth weight (LBW) group, but the difference was reduced to 4.8 points (95% CI, 1.1 to 8.5) after adjusting for confounding parental demographic a nd childrearing factors. The verbal IQ was similar for the two groups after such adjustment. Paternal education was the main confounding var iable, and demographic factors such as parental education and family i ncome were much stronger predictors of child IQ than birthweight or fa ctors related to the childrearing environment. There was no evidence t hat the cognitive development of low birthweight children was more sen sitive to a non-optimal childrearing environment than that of normal b irthweight children. These findings indicate that the risk of impaired cognitive development increases with decreasing socioeconomic status, and that this risk is much larger than, and independent of, the small risk attributable to low birthweight.