Ethnic differences in cognitive development in the first 7 years: does maternal generational status matter?

BACKGROUND: Differences in cognitive development have been observed across a variety of ethnic minority groups but relatively little is known about the persistence of these developmental inequalities over time or generations. METHODS: A repeat cross-sectional analysis assessed cognitive ability scores of children aged 3, 5 and 7 years from the longitudinal UK Millennium Cohort Study (white UK born n=7630; Indian n=248; Pakistani n=328; Bangladeshi n=87; black Caribbean n=172; and black African n=136). Linear regression estimated ethnic differences in age normed scores at each time point. Multivariable logistic regression estimated within-group generational differences in test scores at each age adjusting stepwise for sociodemographic factors, maternal health behaviours, indicators of the home learning environment and parenting styles. RESULTS: The majority of ethnic minority groups scored lower than the white UK born reference group at 3 years with these differences narrowing incrementally at ages 5 and 7 years. However, the black Caribbean group scored significantly lower than the white UK born reference group throughout early childhood. At 3 years, Pakistani, black Caribbean and black African children with UK born mothers had significantly higher test scores than those with foreign born mothers after baseline adjustment for maternal age and child gender. Controlling for social, behavioural and parenting factors attenuated this generational advantage. By 7 years there were no significant generational differences in baseline models. CONCLUSIONS: Ethnic differences in cognitive development diminish throughout childhood for the majority of groups. Cumulative exposure to the UK environment may be associated with higher cognitive development scores.