Longitudinal analysis of cognitive development across childhood and adolescence: evidence from the UK Millennium Cohort Study

Abstract

BackgroundPoor cognitive ability in childhood may lead to poor outcomes across the life course. Thus, isolating clusters of children who share similar trajectories of cognitive development across the childhood developmental stages will facilitate the development of more precise interventions. This study sought to identify trajectories of cognitive development across childhood and early-adolescence. We then aimed to assess associations of these trajectories with demographic factors, socioeconomic circumstances, parenting and school environment. MethodWe used data from the UK Millennium Cohort study on 11564 children aged between 3 and 14 years. Cognitive development was assessed through standard cognition tests administered individually to cohort members at ages 3, 5, 7, 11, and 14 years. The British Ability Scales II tests were used at ages 3–11 years and a word activity test at age 14 years. Standardised test scores were used to classify children into two groups to create a binary measure with children classified as having cognitive problems if they scored –1·25 SDs below the cohort mean. We used a group-based trajectory model to identify trajectories of cognitive development for children. Multinomial regression models were used to assess associations. FindingsFour trajectories were identified: early childhood cognitive problems (719 [6·2%] of sample), late childhood cognitive problems (1084 [9·4%]), persistent cognitive problems (498 [4·3%]) and low cognitive problems (9263 [80·1%]). In the multivariable regression analysis increasing deprivation, low maternal education and low parental involvement with school increased the risk of being in all of the problem groups compared with children with low cognitive problems. Males, being bullied and those of non-White ethnicity had an increased risk of being in the persistent problems group. Males, not being read to and those of non-White ethnicity had an increased risk of being in the early problems group. Females, being bullied and not enjoying school had an increased risk of being in the late problems group. InterpretationDeprivation is associated with cognitive problems throughout childhood. Gender, ethnicity, the school environment, and aspects of parenting are associated with cognitive problems at different stages of childhood. These findings highlight possible targets for interventions. Using a contemporary nationally representative UK cohort, to identify characteristics of children with similar trajectories of cognitive development, strengthens generalisability of findings to inform UK policy. FundingUK National Institute for Health Research Doctoral Research Fellowship Programme.