Direct and indirect effects of maternal intelligence, maternal age, income, and home environment on intelligence of preterm, low-birth-weight children

Low birth weight (LBW) infants are at elevated risk for adverse developmental outcomes, including impaired cognition. From a public health perspective, interventions designed primarily to prevent and/or secondarily to avert intellectual impairments could have substantial impact on social and fiscal costs associated with LBW. But LBW is a heterogenous condition correlated with demographic, biological, psychological, and social variables. In this study we examined direct and indirect effects of maternal intelligence, age, income, and home environment on 3-year intelligence among premature LBW children. Hierarchical regression analyses were employed to determine the extent to which SES (measured by family income) and home environment mediate effects of maternal IQ and age on child IQ. Maternal IQ was found to have major direct and indirect consequences. Indirect effects were mediated by income and home environment. A small part of the influence of income is explained by home environment. Taken together with results of other studies, these findings suggest that standard family interventions to improve cognitive outcome for children of poor and intellectually compromised women are not likely to produce impressive results.