African-American Children

At all levels of family income, African-American children receive lower scores on subtests of IQ tests and on reading and writing achievement tests than European-American children. Several factors contribute to these differences, including cultural bias in IQ tests and differences in school quality, teacher expectancy, the home learning environment, and economic resources not reflected in current income. Racial disparity in children's early physical health status also may be a factor. African-American children, compared to European-American children, have higher rates of iron deficiency anemia, elevated blood lead, and low birthweight (less than or equal to 2,500 grams (5 pounds, 8 ounces) at birth). Racial disparities in anemia and elevated blood lead exist at all income levels but are especially significant among children who are poor.

The adverse effects of these physical health conditions on children's development are well documented. Iron-deficiency anemia in infancy adversely affects brain development partly by affecting the neurotransmitter function and myelin formation; it is consistently associated with poorer scores on cognitive and motor functioning. Children with elevated blood lead levels, compared to those with lower lead burdens, have slightly decreased scores on measures of intelligence, poorer school performance and achievement test scores, shorter attention spans, and increased impulsiveness. Although the vast majority of low birthweight children have normal outcomes, as a group they have more problems in cognition, attention, and neuromotor functioning during middle childhood and adolescence.

Elevated levels of lead in the blood is more prevalent among African-American children because poverty and housing discrimination have relegated African-American families in disproportionate numbers to poor, older, urban neighborhoods. Housing units in these neighborhoods often contain deteriorating lead-based paint and lead-contaminated dust. In addition, these neighborhoods tend to be near industrial areas, which increases exposure to lead gasoline. It remains a puzzle why low birthweight births are more common among African Americans than among any other ethnic group, regardless of the mother's educational level (an indicator of socioeconomic status). Higher teen pregnancy rates among African Americans do not explain this race differential and genetic hypotheses have been discounted (McLoyd and Lozoff 2001).