Does birth weight affect academic performance later in life?

Lower birth weight is usually associated with poorer cognition. Whether birth weight is a target of intervention or a biomarker of other factors is unknown because lower birth weight might indicate that people who have heavier babies have other advantages that facilitate academic performance, such as higher socio-economic position. In the absence of randomized controlled trials showing the effect of birth weight on academic performance, Professor Schooling and colleagues compared academic performance by genetically predicted birth weight (based on twin status or genetic markers) in a population representative Chinese birth cohort and the Social Science Genetic Association Consortium study of 126,559 Caucasians. Academic performance was unrelated to birth weight. Years of schooling and college completion were also unrelated to birth weight. This study casts doubt on birth weight contributing to academic performance.

In summary, Professor Schooling says, “Lower birth weight per se is unlikely to affect cognition. Interventions should focus on the contextual factors generating any observed correlations.”

Lin SL, Leung GM, Schooling CM, The effect of birth weight on academic performance: instrumental variable analysis, Am J Epidemiol 22^nd march 2017