ArticleBMJ (Clinical research ed.)2006
Comparison of academic performance of twins and singletons in adolescence: follow-up study.
Article in BMJ (Clinical research ed.), 2006. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 54 papers, 2 of them syntheses that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
54 citing papers in PubMed, 2 syntheses or guidelines pooled it.
- Neurodevelopmental Outcomes of Twins Compared With Singleton Children: A Systematic Review.Twin research and human genetics : the official journal of the International Society for Twin Studies · 2018Pooled it
- Genetic and environmental influences on impulsivity: a meta-analysis of twin, family and adoption studies.Clinical psychology review · 2011Pooled it
- Education in Twins and Their Parents Across Birth Cohorts Over 100 years: An Individual-Level Pooled Analysis of 42-Twin Cohorts.Twin research and human genetics : the official journal of the International Society for Twin Studies · 2017Trial
- Moderating effects of educational inequality on education polygenic scores, attained education and dementia-risk relationships.SSM - population health · 2026Article
- Twins and their singleton siblings differ in language, cognition, and social-emotional development.Child development · 2026Article
- Non-cognitive skills mediate education-related polygenic score associations with academic achievement across development.Nature communications · 2026Article
- Expanding the Danish Twin Registry into its Third Century: Secular Trends in Twin Births and Survival.Behavior genetics · 2026Article
- Is educational attainment protective against developing dementia? A twin study of genetic and environmental contributions.European journal of epidemiology · 2025Article
- APOE Genotype, ApoE Plasma Levels, Lipid Metabolism, and Cognition in Monozygotic Twins with, at Risk of, and without Affective Disorders.Journal of clinical medicine · 2024Article
- Very Early-Life Risk Factors for Developing Dementia: Evidence From Full Population Registers.The journals of gerontology. Series B, Psychological sciences and social sciences · 2023Article
- Special Issue editorial: Leveraging genetically informative study designs to understand the development and familial transmission of psychopathology.Development and psychopathology · 2022Article
- Childhood inhibition predicts adolescent social anxiety: Findings from a longitudinal twin study.Development and psychopathology · 2022Article
- Language Variation in the Writing of African American Students: Factors Predicting Reading Achievement.American journal of speech-language pathology · 2021Article
- Sixth grade academic achievement among children conceived with IVF: a population-based study in Texas, USA.Journal of assisted reproduction and genetics · 2021Article
- Conduct disorder and somatic health in children: a nationwide genetically sensitive study.BMC psychiatry · 2020Article
- Neurodevelopmental outcome of preterm twins at 5 years of age.Pediatric research · 2020Article
- Lifespans of Twins: Does Zygosity Matter?Genes · 2019Article
- Longitudinal Links Between Gambling Participation and Academic Performance in Youth: A Test of Four Models.Journal of gambling studies · 2018Article
- The utility of twins in developmental cognitive neuroscience research: How twins strengthen the ABCD research design.Developmental cognitive neuroscience · 2018Review
- Associations between birth characteristics and age-related cognitive impairment and dementia: A registry-based cohort study.PLoS medicine · 2018Article
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Authors and funding
6 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectivesTo determine whether twins in recent cohorts show similar academic performance in adolescence to singletons and to test the effect of birth weight on academic performance in twins and singletons.
designFollow-up study.
settingDenmark.
participantsAll twins (n=3411) and a 5% random sample of singletons (n=7796) born in Denmark during 1986-8.
main outcome measuresTest scores in ninth grade (age 15 or 16), birth weight, gestational age at birth, parents' age, and parents' education.
resultsNinth grade test scores were normally distributed, with almost identical mean and standard deviations for twins and singletons (8.02 v 8.02 and 1.05 v 1.06) despite the twins weighing on average 908 g (95% confidence interval 886 to 930 g) less than the singletons at birth. Controlling for birth weight, gestational age at birth, age at test, and parents' age and education confirmed the similarity of test scores for twins and singletons (difference 0.04, 95% confidence interval -0.03 to 0.10). A significant, positive association between test score and birth weight was observed in both twins and singletons, but the size of the effect was small: 0.06-0.12 standard deviations for every kilogram increase in birth weight.
conclusionsAlthough older cohorts of twins have been found to have lower mean IQ scores than singletons, twins in recent Danish cohorts show similar academic performance in adolescence to that of singletons. Birth weight has a minimal effect on academic performance in recent cohorts; for twins this effect is best judged relative to what is a normal birth weight for twins and not for singletons.
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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.