Article Text
Abstract
Objectives Preterm birth can affect cognition, but other factors including parental education and intelligence may also play a role, but few studies have adjusted for these potential confounders. We aimed to assess the impact of gestational age (GA), late preterm birth (34 to <37 weeks GA) and very to moderately preterm birth (<34 weeks GA) on intelligence, attention and executive function in a population of Danish children aged 5 years.
Design Population-based prospective cohort study.
Setting Denmark 2003–2008.
Participants A cohort of 1776 children and their mothers sampled from the Danish National Birth Cohort with information on GA, family and background factors and completed neuropsychological assessment at age 5.
Primary outcome measures Wechsler Preschool and Primary Scale of Intelligence-Revised, Test of Everyday Attention for Children at Five and Behaviour Rating Inventory of Executive Function scores.
Results For preterm birth <34 weeks GA (n=8), the mean difference in full-scale intelligence quotient(IQ) was −10.6 points (95% CI −19.4 to −1.8) when compared with the term group ≥37 weeks GA (n=1728), and adjusted for potential confounders. For the teacher-assessed Global Executive Composite, the mean difference was 5.3 points (95% CI 2.4 to 8.3) in the adjusted analysis, indicating more executive function difficulties in the preterm group <34 weeks GA compared with the term group. Maternal intelligence and parental education were weak confounders. No associations between late preterm birth 34 to <37 weeks GA (n=40) and poor cognition were shown.
Conclusions This study showed substantially lower intelligence and poorer executive function in children born <34 weeks GA compared with children born at term. GA may play an important role in determining cognitive abilities independent of maternal intelligence and parental education. Studies with larger sample sizes are needed to confirm these findings, as the proportion of children born preterm in this study population was small.
- attention
- child development
- executive function
- gestational age
- intelligence
- preterm birth
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Footnotes
Contributors EPFS contributed to the conception and design of the study, performed data management and statistical analyses, analysed and interpreted the data, drafted the initial manuscript and wrote the final manuscript with contributions from the coauthors. JAS and FJB contributed to the conception and design of the study, assisted with statistical analyses and interpretation of the data and critically reviewed and revised the manuscript. ELM and USK conceptualised and designed the study, analysed and interpreted the data and critically reviewed and revised the manuscript. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
Funding This work was supported by a scholarship granted by the Novo Nordisk Foundation. The LDPS was supported primarily by Centers for Disease Control and Prevention, Atlanta, Georgia, USA, and also from the Danish National Board of Health, the Lundbeck Foundation, Ludvig & Sara Elsass’ Foundation, the Augustinus Foundation and Aase & Ejnar Danielsen’s Foundation. The Danish National Research Foundation established the Danish Epidemiology Science Center that initiated and created the DNBC. Besides a major grant from this Foundation, additional support for the DNBC was obtained from the Pharmacy Foundation, the Egmont Foundation, the March of Dimes Birth Defects Foundation, the Augustinus Foundation and the Health Foundation.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The data collection for the LDPS was approved by the DNBC Board of Directors, the DNBC Steering committee, the regional Ethics Committee, the Danish Data Protection Agency and the Institutional Review Board at the Centers for Disease Control and Prevention. Signed informed consent was obtained for the LDPS. The current study was further approved by the Danish Data Protection Agency (file number 2012-58-0004).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement No data are available.