Spillover effects of gestational age on sibling’s literacy

ABSTRACT

Adverse health events within families can harm children’s development, including their early literacy. Using data from a longitudinal Wisconsin birth cohort, we estimated the spillover effect of younger siblings’ gestational ages on older siblings’ kindergarten-level literacy. We sampled 20,014 sibling pairs born during 2007-2010 who took Phonological Awareness Literacy Screening-Kindergarten tests during 2012-2016. Exposures were gestational age (completed weeks), preterm birth (gestational age <37 weeks), and very preterm birth (gestational age <32 weeks). We used gain-score regression – a fixed effects strategy – to estimate spillover effects. A one-week increase in younger siblings’ gestational age improved the older siblings’ test score by 0.011 SD (95% confidence interval: 0.001, 0.021 SD). The estimated spillover effect was larger among siblings whose mothers reported having a high school diploma/equivalent only (0.024 SD; 95% confidence interval: 0.004, 0.044 SD). The finding underscores the networked effects of one individual’s early-life health shocks on their family members.

KEYWORDS:

• Gestational age
• literacy
• siblings
• spillover effects

Acknowledgements

Data used for this study were provided by the Wisconsin Department of Children and Families, Department of Health Services, and Department of Public Instruction. The content is solely the responsibility of the authors and does not necessarily represent the views of supporting agencies and data providers. Additionally, supporting agencies and data providers do not certify the accuracy of the analyses presented. We thank Steven Cook, Dan Ross, Jane Smith, Kristen Voskuil, and Lynn Wimer for data access and programming assistance, and we thank John Mullahy and Paul Peppard for comments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data used for this project are not publicly available.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The study was supported by the following sources: the Health Resources and Service Administration through the University of Wisconsin Primary Care Research Fellowship (T32HP10010); the Eunice Kennedy Shriver National Institute for Child Health and Human Development (T1R01HD102125); and the Eunice Kennedy Shriver National Institute for Child Health and Human Development through the Center for Demography and Ecology at the University of Wisconsin (T32 HD007014-42).

Notes on contributors

David C. Mallinson

David Mallinson is a postdoctoral fellow in the Department of Family Medicine and Community Health at the University of Wisconsin-Madison School of Medicine and Public Health. His research concerns the effect of pre- and early-life health on the development and wellbeing of children and their family members. He also evaluates the effectiveness of prenatal care interventions in low-income populations.

Felix Elwert

Felix Elwert is a Professor of Sociology, Population Health Sciences, and Biostatistics at the University of Wisconsin-Madison. He conducts research on social and racial inequality in the United States and Europe and develops methods for applied causal inference in the social and health sciences. He is the editor-in-chief of Sociological Methods & Research.

Deborah B. Ehrenthal

Deborah Ehrenthal is a Professor in the Department of Biobehavioral Health and the director of the Social Science Research Institute at the Pennsylvania State University. She specializes in using administrative data to investigate disparities in maternal and child health and to evaluate the impact of prenatal health and health care on the wellbeing of infants, mothers, and their families.