Robert M. Joseph, Stephen R. Hooper, Tim Heeren, Hudson P. Santos Jr, Jean A. Frazier, Lauren Venuti, Ann Foley, Caitlin K. Rollins, Karl C. K. Kuban, Rebecca C. Fry, Thomas M. O’Shea, for the ELGAN Study Investigators
Paediatr Perinat Epidemiol. 2022; 36: 654- 664. doi: 10.1111/ppe.12893
Background
Children born extremely preterm (EP) are at increased risk of cognitive deficits that persist into adulthood. Few large cohort studies have examined differential impairment of cognitive function in EP-born adolescents in relation to early life risk factors, including maternal social disadvantage, gestational age at delivery, and neonatal morbidities prevalent among EP neonates.
Objectives
To assess cognitive abilities in relation to early life risk factors in an EP-born cohort at 15 years of age.
Methods
681 of 1198 surviving participants (57%) enrolled from 2002 to 2004 in the Extremely Low Gestational Age Newborn Study returned at age 15 years for an assessment of cognitive abilities with the Wechsler Abbreviated Scale of Intelligence-II and the NIH Toolbox Cognition Battery (NTCB) verbal cognition and fluid processing composites, the latter of which measured executive functions and processing speed. Three cognitive outcomes, WASI-II IQ, NTCB verbal cognition, and NTCB fluid processing, were analysed for associations with maternal social disadvantage and gestational age. Mediation of maternal social disadvantage by gestational age and mediation of gestational age by neonatal morbidities were also examined.
Results
Test scores were lower for NTCB fluid processing relative to IQ and NTCB verbal abilities. Social disadvantage and gestational age were associated with all three cognitive outcomes. Mediation analyses indicated partial mediation of gestational age associations with all three outcomes by neonatal morbidities but did not support mediation by gestational age of social risk associations with cognitive outcomes.
Conclusions
Greater maternal social disadvantage and lower gestational age are associated with less favourable cognitive outcomes among EP-born adolescents at 15 years of age. Neonatal morbidities partially mediate associations between lower gestational age and cognitive outcomes. These findings highlight the need for improved medical and remedial interventions to mitigate the risk of poor cognitive outcomes among EP-born adolescents.