Ghirardi, G., The Development of Body Mass Index from Adolescence to Adulthood: A Genotype-Family Socioeconomic Status Interaction Study. Here the pre-print (R&R)
Abstract
Body weight in adolescence and adulthood may result from the interplay between individuals' genetic characteristics and the social context in which they grow up, such as family socioeconomic status (SES). However, evidence on the interaction between genetic propensity for high body mass index (BMI) and family SES remains inconclusive. This study investigates whether the genetic propensity for high BMI impacts BMI differently among individuals from high-SES versus low-SES families and whether this effect varies with age. Three theoretical frameworks—compensatory advantage or diathesis-stress model and social push model —are tested to predict the moderating effect of family SES on the genetic association with BMI. Drawing on data from the National Longitudinal Study of Adolescent to Adult Health (Add Health), I use the polygenic index for BMI (BMI PGI) to measure genetic propensity for body weight and analyze it at various life stages: adolescence (≃ 16 years old), early adulthood (≃ 22 years old), adulthood (≃ 28 years old), and later adulthood (≃ 37 years old). Results indicate that the BMI PGI is more predictive of BMI in individuals from low-SES families than those from high-SES families. This interaction is observed across both younger and older age groups, suggesting that the interaction between BMI PGI and family SES persists throughout the life course, especially among those who show high levels of BMI – as revealed through unconditional quantile regression. These findings underscore the importance of adopting a life-course perspective in gene-environment interaction studies and highlight the need to account for potential heterogeneity in the gene-environment effect across different levels of BMI.Ghirardi, G., & Gioachin, F. Center-based ECEC Closes Gaps, Others May Widen Them: A Decomposition of How Different Childcare Arrangements Shape Early Educational Inequality. Here the pre-print (R&R)
Abstract
This research note investigates how childcare arrangements under age three affect early social inequalities in children’s competencies, relying on a novel decomposition approach (Yu and Elwert 2023). This approach allows us to provide a comprehensive evaluation of different childcare arrangements within a potential outcome framework, revealing not only the overall relevance of each childcare arrangement but also the importance of specific channels impacting social disparities such as prevalence (unequal exposure), effect (heterogeneous effect), and selection (within-group propensity to treatment). Using the newborn cohort of the German National Educational Panel Study (NEPS - SC1), we assess the impact of early childhood education and care (ECEC), family day-care, grandparental care, and exclusive parental care on children’s competencies in mathematics and vocabulary at ages 4 and 5. Findings highlight ECEC as the most effective approach in reducing social disparities, positively influencing children from lower socio-economic backgrounds. Conversely, exclusive parental care and family day-care increase social disparities, benefiting children from higher socio-economic backgrounds while negatively affecting those from lower backgrounds. This comprehensive evaluation identifies channels impacting social inequalities, contributing to understanding the nuanced role of childcare arrangements in shaping early social inequalities in children’s competencies.Breinholt, A., & Ghirardi, G., Interactions between Childhood Socioeconomic Status and Genotype on Educational Outcomes: A Novel Theoretical Typology and Meta-Analysis of Molecular Studies. Here the pre-registration
Abstract
A growing body of research investigates whether genetic influences on educational outcomes can be suppressed or boosted by the environment in which an individual lives. Indeed, several studies have examined the interaction between the genetic propensity for education and the socioeconomic status (SES) of the family of origin, the neighborhood, or school - so-called GxSES studies. However, results are mixed. Some studies find stronger associations between genetic propensities and educational outcomes in high-SES environments, while other studies find stronger associations in low-SES environments. In this work, we conduct a systematic review and meta-analysis of studies that investigated the interaction between genetic propensity for education and SES on measures of educational attainment and achievement. We focus on studies relying on molecular genetic information in the form of polygenic indices (PGI). This study aims to answer the following questions: (1) Does the genetic propensity for education matter more for educational outcomes in high or low-SES environments? (2) Which factors may explain the inconsistent findings of the previous literature? To address these questions, we collect results from both published and working papers investigating the interaction of interest and using molecular data.Bernardi, F., Ferrara, A. & Ghirardi G. Unequal Chance: Modeling Luck in Educational Inequality.
Abstract
Sociology has paid limited attention to the role of luck in shaping individual socioeconomic outcomes. This study examines how luck contributes to educational disparities by family socioeconomic status (SES). We define luck as chance events that provide or deplete resources for educational attainment and propose that unexplained variance in regression models partly captures their influence. Building on the Breen and Goldthorpe model of educational inequality, we introduce a stochastic component and derive a novel hypothesis: luck has a greater impact when structural resources and individual propensity for education are misaligned, specifically for low-SES students with high educational propensity, and high-SES students with low propensity. We test this hypothesis using variance function regression and replicate the analyses on two U.S. datasets, using sibling fixed-effects models. We find support for our hypothesis and conclude by reflecting on the implications for the emerging sociology of luck and broader research on social stratification.