Poverty and behavior problems trajectories from 1.5 to 8years of age: Is the gap widening between poor and non-poor children?

Abstract

Poverty has been associated with high levels of behavior problems across childhood, yet patterns of associations over time remain understudied. This study aims: (a) to examine whether poverty predicts changes in behavior problems between 1.5 and 8years of age; (b) to estimate potential selection bias for the observed associations. We used the 1998-2006 waves of the Quebec Longitudinal Study of Child Development (N=2120). Main outcomes were maternal ratings of hyperactivity, opposition and physical aggression from 1.5 to 8years of age. Linear mixed-effects models were used to assess the longitudinal association between poverty and behavior problems. Models were re-estimated adjusting for wave nonresponse and using multiple imputation to account for attrition. Poverty predicted higher levels of behavior problems between 1.5 and 8years of age. Poverty predicted hyperactivity and opposition in a time dependent manner. Hyperactivity [Bpoverty*age=0.052; CI 95% (0.002; 0.101)] and opposition [Bpoverty*age=0.049; CI 95% (0.018; 0.079)] increased at a faster rate up to age 5years, and then decreased at a slower rate for poor than non-poor children. Physical aggression decreased at a steady rate over time for all children [Bpoverty*age=-0.030; p=0.064). Estimates remained similar when accounting for attrition. Poverty predicted higher levels of behavior problems between 1.5 and 8years of age. The difference between poor and non-poor children was stable over time for physical aggression, but increased with age for hyperactivity and opposition. Attrition among poor children did not compromise the validity of results.